Add mono_class_can_access_class so the verifier can check if one type can access another.
[verifier]Fill in the assembly name so checks for InternalsVisibleTo don't crash.
[verifier]A type constraint must be visible to the generic type definition. Fixes #11263.
[verifier]Add test case for #11263.
[verifier] Properly merge stacks when both ends have the same boxed valuetype.

Fixes System.Data.Services.Client.dll failure on wrench.
[verifier] Add regression test for stack merge of boxed valuetypes.
[verifier]Handle variance correcty when checking delegate parameters.

	* verify.c (verifier_class_is_assignable_from): If the target
	is a variant interface, check if the candidate is one too that
	is a direct match.
[verifier] Add regression test for the case where the function being used in a delegate returns a variant interface.