Expose mono_class_is_open_constructed_type to Unity to allow us to check to see if the class is not yet fully instantiated prior to asttempting to call mono_object_new on it.

* Also cleaning up a minor leak of a MonoError in mono_unity_class_inflate_generic_class

Reintroduce https://github.com/Unity-Technologies/mono/commit/6c41f64f25da4c12b237b6bb51765722e0dd5281#diff-0ff844e784e15d2542b71c85d2c0133e

This is so we will not get errors when resolving strong named assemblies for a version not loaded.
This option will ignore the version

Revert "Reintroduce https://github.com/Unity-Technologies/mono/commit/6c41f64f25da4c12b237b6bb51765722e0dd5281#diff-0ff844e784e15d2542b71c85d2c0133e"

This reverts commit 9d9a0eda.

Reintroduce https://github.com/Unity-Technologies/mono/commit/6c41f64f25da4c12b237b6bb51765722e0dd5281#diff-0ff844e784e15d2542b71c85d2c0133e

This is so we will not get errors when resolving strong named assemblies for a version not loaded.
This option will ignore the version

Without proper alignment, this may lead to reference types
being stored at non-pointer aligned offsets. Among other
issues this may lead to the GC not scanning those pointers
properly.

* mono_custom_attrs_construct_by_type allows unity to have a chance at handling the error if one arises instead of fatally asserting
* mono_unity_error_convert_to_exception allows unity to take the provided MonoError and fetch the MonoException object within to log into the editor as the exception that was thrown.

This change has associated unity changes in order to fix (case 1255935)

Emitting error 100 times is plenty.

This change applies a similar fix for exFAT partitions as was applied
for FAT32 partitions earlier. For exFAT partitions, the invalid inode
value seems to be 1 though.

Add System.Collections.Generic include to objects.cs

This brings us in line with GetDiskFreeSpaceExW on Windows as well as .NET Core.

Attempting to guard against MONO_HANDLE_IS_NULL performing a null deref while checking for null. Sourced from: https://github.com/mono/mono/pull/9188 blindfix for case 1232819

sets.

Making associated change to type_in_image to also check the constrained type for a match. Re-adding asserts now they they no longer trigger.

updating to K&R coding convention

Fixes https://github.com/mono/mono/issues/18127.

Fixes #8915

Fixes issue in mono_class_init where we would return immediately instead of jumping to the cleanup routine. This would leave init_list in a dirty state for subsequent calls leading to recursive type definitions being thrown incorrectly. (case 1191002)

[metadata] Fields whose types are gparams with a reference type constraint aren't blittlable. (#15761)

* [metadata] Fields whose types are gparams with a reference type constraint
aren't blittlable.
Don't try to layout the field to find out if it's blittable.
For gshared gparams, follow the blittability of the constraint.

Fixes certain recursive examples.

```
using System;

namespace TestRecursiveType
{
    class Program
    {
        static void Main(string[] args)
        {
            SubClass subC = new SubClass();
            Console.WriteLine(subC.GetTest());
        }
    }

    public struct ValueTest<U>
    {
        // When U is instantiated with T, from BaseClass, we know it'll be a
	// reference field, so we know the instantiation ValueTest<T> won't
	// be blittable.
        public readonly U value;
    }

    public abstract class BaseClass<T> where T : BaseClass<T>
    {
        public ValueTest<T> valueTest = default(ValueTest<T>);
    }

    public class SubClass : BaseClass<SubClass>
    {
        private String test = "test";

        public string GetTest()
        {
            return test;
        }
    }
}
```

Fixes https://github.com/mono/mono/issues/15760

---

The failure is happening when we are doing mono_class_setup_fields ("BaseClass<T>") which needs to decide for each field whether it is blittable or not. So therefore we are trying to decide if ValueTest<T> (that is: the ValueTest<U> field inside BaseClass<T>) is blittable or not.

So we instantiate U with T.
Now to decide whether VaueTest<T> is blittable or not, we look at every field.
So then we look at T value.
To decide if T is blittable we first check if it's a reference type.

That check is currently inadequate for generic parameters - what the PR adds is the ability to see if theres a T : class constraint or a T : C constraint - where C is some class. As soon as we know that T's constraint will force it to be a reference type we can definitely say that T won't be blittable without having to initialize C, at all.

Previously, Mono would see that T is some kind of type for which it couldn't definitively decide that it's a reference type and it would call: mono_class_setup_fields (field_class) which would then try to setup the fields of the parent class BaseClass<T>. And that would hit the recursion check.

Unity cherry-pick note: Needed to bring MONO_CLASS_IS_INTERFACE_INTERNAL
and mono_class_get_valuetype_class forward

Previously, 5174f7ed was an attempt to
correct this issue. However, the `#define` scheme for Mono changed since
then, so `PLATFORM_MACOSX` became `HOST_DARWIN`.

This change uses the proper define to correct Unity case 1166108.

* improve mempool chunk reporting in order to get exact range for each chunk

* added mono_unity_class_for_each in order to allow for simple iteration logic over all initialized classes in the VM

* added mono_type_get_name_chunked in order to report type names in null terminated chunks.
A good example for this can be using a preallocated instance of core::string as user_data for the callback which will then append onto the preallocated string

* added mono_unity_image_set_mempool_chunk_foreach in order to report memory blocks from the VM heap
added mono_unity_domain_mempool_chunk_foreach in order to report memory blocks inside the current domain's memory pool
added mono_unity_root_domain_mempool_chunk_foreach in order to report memory blocks inside the root domain's memory pool
added mono_unity_assembly_mempool_chunk_foreach in order to report memory blocks inside an assembly's image's memory pool
added mono_unity_class_get_data_size in order to return static field data size for a MonoClass
added mono_unity_class_get_static_field_data in order to access static fields memory for a given MonoClass
added mono_unity_class_field_is_literal in order to find out if the attributes
added mono_unity_start/stop_gc_world() in order to control the GC world state
added mono_unity_gc_heap_foreach in order to report each allocated GC heap section
added mono_unity_gchandles_foreach_get_target in order to report all gc handle targets tracked by the garbage collector
added mono_unity_object_header_size in order to report mono object header size
added mono_unity_array_object_header_size in order to report mono array object header size
added mono_unity_offset_of_array_length/bounds_in_array_object_header in order to report the offset of the length/bounds of the array within the header
added mono_unity_allocation_granularity in order to report the minimum allocation granulariy inside the vm
added mono_unity_get_name_full_chunked in order to extract a types name in chunks
added mono_unity_type_is_static in order to report if the given type is static
added mono_unity_type_is_pointer_type in order to report if the given type is a pointer type

* added missing include

* fixed up missing user_data assignment during context initialization for mono_unity_class_for_each

* move type name streaming utility out of class.h/.c

On macOS and FAT32 partitions, we will sometimes get this inode value
for more than one file. It means the file is empty.  When this happens,
the hash table of file shares becomes corrupt, since more then one file
has the same inode. Instead, let's assume it is always fine to share
empty files. (Unity case 950616).

Fix liveness recursion issue (case 1137077). Cherry-pick of https://github.com/Unity-Technologies/mono/commit/0fb8f1f8bf17e6d51059a263680eb87025079028

The format string was incorrect in this case, which leads to this crash
in Unity:

https://crashes.hq.unity3d.com/crashes/5aa00d01b4db11000de20c8e?versions_range=2018.3.5..2019.2.99&date_start=&date_end=&source=

Simply remove the unused `%s` format specifier here.

Revert part of https://github.com/Unity-Technologies/mono/pull/1131
as it causes hangs in calls to CancelSynchronousIo

Reverts part of fix for case 1073634

* Fix race condtion in socket altertable wait implementation on Windows.

* Add support to abort blocking Windows mono_w32file_read/write methods.

[jit] Avoid extending the size of Vector2/Vector3 to 16 bytes. Disable SIMD for these types for now, since the SIMD code can't handle types (#6746)

which are smaller than a SIMD reg.

Fixes https://github.com/mono/mono/issues/6411.