Allow lambdas in this()/super() to close over outer types

[niloc132]

Prior to JDT 3.32, passing a lambda that closes over outer types to this()/super() constructors would result in a compiler error. As of around 3.32 this is now allowed, but the closed-over instance is passed as an item in a "synthetic outer local variable" collection. Each instance in that collection has a field representing the "actual outer local variable", and in this case, that field is null.

Added tests to confirm that the generated code seems consistent, and that running such a lambda affects the expected instance.

Fixes #10065

[niloc132]

Passing full CI build https://github.com/niloc132/gwt/actions/runs/12663353268