Debugger Cleanups

Add folder specifically for UnityScript and Boo assemblies.

Use new MonoBleedingEdge builds.zip for bootstrap Mono.

This starts process of treating them as not part of standard set of
system assemblies. We can easily reference them as needed rather than
assuming they are in all the mono profile directories.

Our previous committed mono versions are too old to build latest mono
and we were falling back to monolite to build.

Make breakpoints_cleanup() safe to call multiple times

Fix crash on android when script debugging is enabled (case 973794)

Fix instrumentation with legacy profiler APIs (case 979612)

Add API to control behavior of thread abort within handler blocks (case 979679).

Fix Windows Socket.Send not blocking (case 984723)

Fix crash on startup when script debugging is enabled due to shared signals between mono and the GC (case 973794)

This matches behavior of receive variants. Fixes blocking send call
where Win32 returns WSAEWOULDBLOCK.

Related to issue https://github.com/mono/mono/issues/6464

Add call instrumentation filter that is enabled for all methods when
legacy embedding API mono_profiler_set_events is used to enable method
enter/leave instrumentation.

Unity unloads domains and this is accomplished via thread abort exceptions.
Mono now matches .NET behavior by not interrupting catch/finally blocks with
thread abort exceptions. This can lead to hangs in Unity as domain unload
blocks until all thread are interrupted.

times when used with IL2CPP, so added some defense against this to
prevent already-cleared hashtables and arrays from being destroyed multiple
times.

Mixed Callstacks: Reduce allocations and perform name calculation outside of lock.

Avoid some code paths on IL2CPP on Mono to avoid test failures.

Enable IPv6 support in the settings files

Always set GC_no_dls when using bdwgc. This fixes a segfault when using our newer Boehm GC on android

It looks like the upstream Mono code uses either the class library PAL
or a fallback to a hard-coded value to enable IPv6 support. The fallback
is not compiled in for the Unity code, so the class library code tries a
final fallback to the settings file. In the old Mono this setting was
present, but it does not exist in the new Mono, as it is not needed
upstream.

This change corrects Unity case 941946 by enabling IPv6 support in the
settings file.

Mono Bleeding Edge for Trunk
case 980742 - Fix 32-bit Windows Standalone failing to load Mono

* IL2CPP debugger fixes for working with Unity players

* Ignoring setp_out sequence points when searching for sequence points that don't correspond to step_out requests.
* Not returning step_out sequence points when retrieving method debug  info.  The step out sequence points have the same offset as other sequence points, but different line numbers.
* Hardened the il2cpp_mono_free_method_signatures() function against multiple calls by setting the method_signatures hash table to null after it is cleared.
* The isActive field in Il2CppSequencePoint should be a uint8_t, not a bool, as it gets incremented.  I think this change was made in the previous C-only type for this struct but not propagated to the C++ version, which is the only version we use now.

* Fixed missed issue with duplicate inner loop variable

Mono Master -> Unity Master

Disable incremental link for release builds. This causes native stack traces to be incorrect for exported mono symbols. Also, move warning as error for 4716 from additional command line args to explicit setting in vcxproj.

CreateLocal works by checking the platform. If it is windows, it uses the windows API or registry depending on api version, UWP, etc. otherwise it checks for the $TZ environment variable. If thats not found. it looks for /etc/localtime.....more obscure platforms like WebGL have no means of obtaining tzdata this way. This means that CreateLocal falls back to setting the TimeZoneInfo.Local time to UTC....this causes functions like DateTime.Now and DateTime.ToLocalTime to convert to UTC, instead of the user's local time.  By using Mono's old icall, we won't be able to convert between arbitrary timezones, but basic time conversion, such as UTC to Local will work.

Mono Bleeding Edge fixes for Trunk
case 947208 - partial fix
case 973494 - Expose mono_object_is_alive

Lots of IL2CPP debugger work.

* add embedding api lost in mono master

* Add MMAP overrides

Debugger suspend threads

* Initial work to properly suspend threads running managed code when the debugger requests it.
Enabling more thread related tests after the thread suspension fix.
* Fixing some issues with step filters that were never working.  Hijacking the jitinfo pointer and storing a Il2CppSequencePoint pointer in it for il2cpp.  We can
use the sequence point to access data we need for filtering, in much the same way mono uses the JitInfo pointer.
* Fixing crashing issues that occur when you generate debug code but don't pass in
the appropriate arguments to initialize the debugger.  We need to check that the debugger has been initialized before performing various debugger-related operations.