There are some cases (superclasses, overridden methods, and so on) where
external dependencies generation can require additional external
dependencies.
* Generate missing IR parameter declarations in external stubs
* Use origin = FAKE_OVERRIDE in external IR stubs for fake overrides
* Set .parent in external IR stubs
* Set .parent in IR generated by some utility methods
Such references require proper scope so that local symbols are bound.
Example:
```
fun <T> outer() {
abstract class ALocal<S : T> {
abstract fun bar()
}
class Local<S : T> : ALocal<S>() {
override fun bar() {}
}
}
```
Here local classes have type parameters with upper bounds depending on
function type parameters, and members overriding members in other local
classes.
Dmitry Petrov