This is a follow-up to b497f39c29. It
turns out that it didn't help because `IrFunction.returnType` throws
exception, and checking for `IrUninitializedType` in `IrType.render` was
already too late. Throw and catch specific exception instead.
Also add function name into the exception message for better diagnostics
elsewhere (can't compute the full FQ name because in cases like
KT-42020, the parent is also uninitialized).
Alexander Udalov
2573eaa77f