Use a passed in Isolate/Heap directly rather than using GetIsolate() on
HeapObjects which may not in future be tied to an isolate.

Bug: v8:7786
Change-Id: I89d8706544aa135049434cf20c4e1308474c678b
Reviewed-on: https://chromium-review.googlesource.com/1089334Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Commit-Queue: Dan Elphick <delphick@chromium.org>
Cr-Commit-Position: refs/heads/master@{#53569}