With this change debugger requests yield(await) positions from kernel builder so it can confirm which frame handles what exceptions.
This also renames ':completer' to ':async_completer' in constructed kernel, so it is compliant with what VM expects to see(and updates test expectations accordingly).
Further it fixes async stack navigation for sync-async that became default in dart vm since first version went for the review((uses `future` getter, rather than property).
It also makes `future` getter non-debuggable to allow stepping-out of async methods.
Make Handle zone-scoped. Clean up frame counter var name.
Bug: https://github.com/dart-lang/sdk/issues/29056
Change-Id: Ia71f3c851a6b313655b57dad28c296f5dd081eda
Reviewed-on: https://dart-review.googlesource.com/54640
Commit-Queue: Alexander Aprelev <aam@google.com>
Reviewed-by: Siva Annamalai <asiva@google.com>
Alexander Aprelev
e71bd048e5