+ Apply correct default on return type of synth record-comp accessor
+ fine tune how @NNBD is applied to record components:
  + already applied during STB.resolveTypeFor(FieldBinding)
  + later ImplicitNullAnnotationVerifier still needs it without default
+ fine tune verification of record component against inherited accessor
+ tests: refresh local source of DefaultLocation & NonNullByDefault

Fixes https://github.com/eclipse-jdt/eclipse.jdt.core/issues/701