Inner class constructors should use the argument instead of reading
outer `this` from a field because if such an access happens before a
delegating constructor call, e.g. when evaluating an argument, a JVM
bytecode validation error will be thrown. (The only operation on `this`
allowed before a delegating constructor call is SETFIELD, and only if
the field in question is declared in the same class.)
Fix for KT-6708: Compiler Error when extending open inner class: "java.lang.RuntimeException: Error generating primary constructor of class InnerB with kind IMPLEMENTATION"
#KT-7421 Fixed
#KT-6708 Fixed
