[VM] Fix SEGV in inliner: Reading the metadata of a function can fail
[VM] Fix SEGV in inliner: Reading the metadata of a function can fail

In this particular case, the kernel-isolate, while executing 'main', was
killed during `Dart_Cleanup()`.  The kill is performed via an OOB message
which will trigger an exception to propagate up.  This will cause the
`Library::GetMetadata()` function to return an error object.

Change-Id: Ie400e50473972875eb338a688bb77c23a562c936
Reviewed-on: https://dart-review.googlesource.com/71163
Reviewed-by: Vyacheslav Egorov <72c81f38df725d8f1832acb9b5bb99563fc2f1b9@google.com>
Commit-Queue: Martin Kustermann <a35dd5b79fac84b2bb3b026a16b8becc55af5961@google.com>

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