Fix JIT on macOS Big Sur beta 6 when running on Apple silicon

Wait on runtime threads to park on joinable thread list during shutdown. (case 1275345)

Sign binaries after lipo-ing them since lipo drops signature added by the linker. Also, use JIT entitlement for signing executables.

Try to copy monodis into monodistribution/bin dir

Unity master fix case 1274470

Unity master fix case 1273662

Fixes https://github.com/mono/mono/issues/20367.

Some light massaging done by @UnityAlex to cherry pick

https://github.com/mono/mono/pull/5599 fixed a race condition during shutdown
when runtime threads have come parts of their way through detach, but still
depend on runtime resources, like GC memory. The fix added runtime threads
to the joinable thread list just before they vanished from mono_thread_manage
radar making sure shutdown waited upon the thread before cleaning up.

The above fix slightly changed the behavior of the finalizer thread since it
waits on joinable threads and will now potential block on threads still
executing code (that involves runtime resources). There’s was an assumption
around the threads on the joinable thread list that they should be very close
to complete when added, so join calls coming from the finalizer thread should
almost never block and if it does, the code that remains to execute should not
involve runtime operations risking deadlock situations. Adding the thread to
the list earlier than previously done expose the shutdown to some potential
theoretical problems.

To mitigate the risk and still solve the race condition this commit adds a
mechanism to keep track of active runtime threads until they park on joinable
thread list. The pending counter will be waited upon by the shutdown
thread, just before it does its regular wait on all joinable threads
(after finalizer thread has stopped) to make sure all runtime threads have
been added to the joinable thread list before waiting upon them. Threads are
added to the joinable thread as late as possible, exactly how it’s been done
in the past by sgen_client_thread_detach_with_lock. Shutdown thread will wait
on runtime threads to appear on the list for a short time and if timeout (pending
runtime thread count not reaching 0 before timeout), it will just print a warning
and continue shutdown.

Getting into a wait state during shutdown due to runtime threads not yet added to
joinable threads list should be very rare (hitting previous race condition that was rare),
triggering the timeout should be even more rare, and if that ever happens, we are exposed
to shutdown race condition as we have had in the past, but now we at least get a warning in
the log making it simpler to analyze further.

This commit also fixes a problem with the debugger thread hitting the same race condition as above.
The shutdown thread stopping the debugger thread didn't completely wait for it to stop using runtime
resources before continue shutdown sequence. This triggers the same race condition as when shutting
down regular runtime threads. This commit makes sure stop_debugger_thread waits on the debugger thread
handle to become signaled (happens at the very end of thread lifetime) before continuing the shutdown
logic.

Remove hack from mono_free_method. Bypassing cleanup here was causing corruption to persist in mscorlib's method hashtable when a rehash occurred.  Unity profiler may need changes to avoid possessing dangling pointers. Same with the mono profiler (as the comment indicates)

https://github.com/Unity-Technologies/mono/commit/7869333c52a2fc2d165effefdbbe97fdf9587b57
https://github.com/mono/mono/pull/9863
https://github.com/Unity-Technologies/mono/commit/f265d9a7838c97d33e8836dfc42d1f946de09041

Needed in order to fix corruption that was occuring to mscorlib's image table on domain reload due to dynamic methods from other images being stored in a hashtable that was not being cleaned up on domain reload.

The NetworkChange event is not supported on Windows (case 1278048)

Fix performance regression due to ldfld usage by Roslyn (case 1276888)

Provide a proper `PlatformNotSupported` exception for the
`NetworkChange` event on Windows, as it is not currently supported.

* Generalize commit 0c6932a9 to support LDARG{0|1|2|3}, LDLOC{0|1|2|3}, LDARGS, LDLOCS, LDARG and LDLOC instead of LDLOC and LDLOCS. Improves generated code similar to issue #60945

Grab part of fix from upstream change: https://github.com/mono/mono/p…

Branch for 2020.2 updates

Merge pull request #1335 from Unity-Technologies/unity-master-method-to-skip-assembly-version-validation

Add option to ignore versions when loading strong named assemblies

Fixing an issue with ManagedWebSocket 

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

https://forum.unity.com/threads/current-netstandard-2-0-system-net-websocket-clientwebsocket-has-a-critical-bug.785366/

Fix handling invalid Windows proxy config

source: https://github.com/mono/mono/pull/12595

Re-adding whitespace to reduce diff noise and make future cherrypicks easier.

[debugger] Access invalid memory address using PointerValue Command. …

* Validate the address that came from IDE using PointerValue. The IDE can send an invalid address and it was crashing mono.

Fixes #18191
Fixes #15612
Co-authored-by: NAleksey Kliger (λgeek) <akliger@gmail.com>

Wrap create_file_to_check_memory_address in #ifndef _MSC_VER check as it's only used in that scope.

Fix random crash on OSX when pushing thread stacks

Fixing hang that would occur when a Debugger.Break would be triggered…

Fixing hang that would occur when a Debugger.Break would be triggered while we are already processing a breakpoint. (case 1254123)

Adding test for debugger hang fix to case 1254123

Added a new property to Tests class which breaks this test.

[corlib] Use Environment.Platform to access the platform, rather than…

[corlib] Use Environment.Platform to access the platform, rather than probing the file system (#6535)

Alternatve patch to: #6533

Update pip install index-url