[vm, gc] Allow old-space collections for allocations during safepoints.
[vm, gc] Allow old-space collections for allocations during safepoints.

Earlier versions of the safepointing mechanism had trouble with this, so we skipped the collections expecting a higher-level caller to eventually clean-up. This is no longer necessary.

Disallow old-space collections under a force-growth scope.

Bug: https://github.com/dart-lang/sdk/issues/39484
Bug: https://github.com/dart-lang/sdk/issues/39493
Change-Id: Id5027899d06a29a307ceeca21dd4d1bc96c94920
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/127102
Reviewed-by: Siva Annamalai <2e618a8cbd7bb6b3d4409061ae407d692a098546@google.com>
Commit-Queue: Ryan Macnak <d738b7f001baf9789095d7dc549cff6de60b011d@google.com>

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