It's needed for situation when we have JS module with expect declaration,
so we refine member scope for that expect declaration and try to
compare to function descriptors (e.g. of `equals` function) from
different class descriptors (expect and actual) and report diagnostic
about name clash. So, since we can earn descriptors from type refinement,
they can be not identical but still equals, so with should use structural
equality to comparing them
Dmitry Savvinov
ab9ff786d7