We are going to deprecate `WITH_RUNTIME` directive. The main reason
behind this change is that `WITH_STDLIB` directive better describes
its meaning, specifically it will add kotlin stdlib to test's classpath.
1. Move jsInteropFunctionsLowering after callable reference lowering,
so it can continue to deal with just functions and function calls.
2. Generate lowered closure class in JsInteropFunctionsLowering because