7109878: The instanceKlass EnclosingMethhod attribute fields can be folded into the _inner_class field.
Summary: Fold instanceKlass::_enclosing_method_class_index and instanceKlass::_enclosing_method_method_index into the instanceKlass::_inner_classes array.
Reviewed-by: never, coleenp
Contributed-by: NJiangli Zhou <jiangli.zhou@oracle.com>