Platform/windows/uum-62035 to unity-main

[TautvydasZilys]

Fix marshaling/interop code emitting ldloc 65535 instruction when calling method on a COM interface. This happened due to unitialized local variable (gc_safe_transition_builder.coop_cominterop_fnptr) getting loaded when "need_gc_safe" is false. This caused the JIT to throw an InvalidOperationException. This fixes case UUM-62035. This bug was indirectly introduced by a previous pull request, which optimized interop call performance and made us take another code path which turned out not to work with COM interop: #1753.

• Should this pull request have release notes?
  • Yes
  • No
• Do these changes need to be back ported?
  • Yes
  • No
• Do these changes need to be upstreamed to mono/mono or dotnet/runtime repositories?
  • Yes
  • No
  • I don't know - do you think we should?

Reviewers: please consider these questions as well! ❤️

Release notes

Fixed UUM-62035 @zilys
Mono: Fixed InvalidProgramException (Invalid IL code in (wrapper managed-to-native) : IL_0004: ldloc 65535)
getting thrown when calling COM interop methods,

Backports

Unity 2023.3 and Unity 2023.2.

Unity repository changes

I added a test for this change on this branch: https://github.cds.internal.unity3d.com/unity/unity/commits/platform/windows/uum-62035. Preferably this test gets merged to trunk together with this bugfix.

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[TautvydasZilys]

Hey folks, what's the current process of:

1. Making sure that the change makes it to trunk together with the playmode test I added in the Unity repository branch?
2. This change is backported?

[UnityAlex]

Hey folks, what's the current process of:

1. Making sure that the change makes it to trunk together with the playmode test I added in the Unity repository branch?

2. This change is backported?

@jhcdunity3d Has been in charge of synching the zips to Unity. He can get you set up.