[generic type] feature: isSubtypeOf is not supported with typeParameters

[surli]

When writing a code like that:

class O<A extends X> {
	<B extends A> B foo() {
		return null;
	}
}

Testing b.isSubtypeOf(a) will always return false for now.
Test has been added in #1157 but is ignored for now. We should start from there.