ILLink doesn't warn for annotation mismatch for derived method implementing a recursive interface

[jtschuster]

In IL it is valid for an abstract Base to implement I but provide no methods. This is not possible in C#, as Base would not be allowed to be missing M. If Base does provide M, the trimmer does warn there (see RequiresCapability/BaseProvidesInterfaceMethodRequiresMismatch.cs). This is a very niche corner case and not the highest priority.

abstract class Base : I
{
}

class Derived : Base
{
    public virtual void M() {} // warning IL2046
}

interface I
{
    [RequiresUnreferencedCode("RUC")]
    void M();
}

See https://github.com/dotnet/runtime/pull/103317#discussion_r1718737150_ for context

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