[vm, gc] Add a release barrier to prevent header initialization of an old object from being ordered after publishing stores of that object.
[vm, gc] Add a release barrier to prevent header initialization of an old object from being ordered after publishing stores of that object.

Compare f4f0831c6900f4fc3d80b852db2d2c1aef4ed7d8, which implicitly removed a barrier from PageSpace::AllocateBlack.

Bug: https://github.com/dart-lang/sdk/issues/39090
Change-Id: I3a9274b90875a6860cb102a238b6f95a6a7b2ff2
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/123004
Reviewed-by: Alexander Markov <239e774fd29abc1267878f57afe1a8a03e0ca887@google.com>
Commit-Queue: Ryan Macnak <d738b7f001baf9789095d7dc549cff6de60b011d@google.com>

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