Avoid devirtualization of invocations of Object members
Avoid devirtualization of invocations of Object members

This CL fixes incorrect devirtualization of invocations of methods and
getters from Object, as null also implements Object members.

Issue: https://github.com/dart-lang/sdk/issues/30480
Change-Id: I39b2e1dd6147482b1331527d61b76841ae401343
Reviewed-on: https://dart-review.googlesource.com/9742
Reviewed-by: Vyacheslav Egorov <72c81f38df725d8f1832acb9b5bb99563fc2f1b9@google.com>
Commit-Queue: Vyacheslav Egorov <72c81f38df725d8f1832acb9b5bb99563fc2f1b9@google.com>

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