Delete `VerifyExpectModifiedAttributesWork`. This test has bit rotted since being...

Delete `VerifyExpectModifiedAttributesWork`.  This test has bit rotted since being made netfx only and now fails due to etw feature removal logic no longer existing. (#89017)

This test dates back to earlier days when the linker had few mechanisms that modified bodies and UnityLinker had many.  I added this test to make sure that test framework support for this attribute didn't break since we depended on it.  Now days, the linker has many mechanisms that modify bodies and `[ExpectBodyModified]` is heavily used in tests.  I don't think there is any value in updating this test to use a different code pattern that results in needing `[ExpectBodyModified]`.