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

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