Adjust IsMetadataVirtual assertion in MethodToClassRewriter

[jcouv]

Fixes #73563

IsMetadataVirtual previously could either:

• give a final answer but this required it to be called after ForceComplete (which may initialize it in SourceMemberContainerTypeSymbolSynthesizeInterfaceMemberImplementation)
• give a partial answer (by passing ignoreInterfaceImplementationChanges)

Previously, in a scenario where comp2 references comp1 as a compilation reference and we emit comp2 and then emit comp1:

1. emitting comp2 called MethodToClassRewriter.VisitCall which called IsMetadataVirtual on a not-yet-completed symbol from comp1. The read from IsMetadataVirtual set the "locked" flag.
2. emitting comp1 completed that symbol from comp1 which would call EnsureMetadataVirtual. This asserted since the "locked" flag was already set

Now, the assertion in MethodToClassRewriter.VisitCall eagerly forces the completion of the symbol from comp1.

[AlekseyTs]

true

Delete? This looks like an artifact from the old state of the comment. #Closed

[AlekseyTs]

It looks like a couple of tests in RefStructInterfacesTests.cs were disabled because of this issue. I think we should enable them in this PR. #Closed

[AlekseyTs]

Done with review pass (commit 1)

[jcouv]

@dotnet/roslyn-compiler for second review. Thanks

[AlekseyTs]

LGTM (commit 2)

[jcouv]

@dotnet/roslyn-compiler for second review. Thanks

[jcouv]

@dotnet/roslyn-compiler for second review. Thanks