[vm/compiler] Make Slot::Get respect field's guarded_cid in AOT mode
[vm/compiler] Make Slot::Get respect field's guarded_cid in AOT mode

Refactoring ddbe22190c41b1993a3c93b67f1bfa57287348f8
wrongly predicated usage of guarded_cid by use_field_guards flag.
However even though field guards are not in use in AOT mode we
still populate guarded_cid from the results of TFA inference.

This change restores pre-refactoring behavior and makes sure we
make use of information inferred by TFA.

Change-Id: I9929d32c763815504801e13c43326f80fd50687b
Reviewed-on: https://dart-review.googlesource.com/c/84633
Commit-Queue: Vyacheslav Egorov <72c81f38df725d8f1832acb9b5bb99563fc2f1b9@google.com>
Reviewed-by: Daco Harkes <930cbae0ca77f1954c53e32620d89cfcca318f00@google.com>

dartino/dart-sdk,dart-archive/dart-sdk,dart-archive/dart-sdk,dart-lang/sdk,dart-archive/dart-sdk,dart-lang/sdk,dart-lang/sdk,dartino/dart-sdk,dart-lang/sdk,dartino/dart-sdk,dart-archive/dart-sdk,dartino/dart-sdk,dart-archive/dart-sdk,dart-archive/dart-sdk,dart-archive/dart-sdk,dartino/dart-sdk,dart-lang/sdk,dartino/dart-sdk,dart-archive/dart-sdk,dartino/dart-sdk,dart-lang/sdk,dart-archive/dart-sdk,dart-lang/sdk,dart-lang/sdk,dartino/dart-sdk,dartino/dart-sdk