Also moves ObjectVerify to GlobalHandles::CopyGlobal from
V8::CopyPersistent (which was the only caller) so it can get hold of an
Isolate*.

Bug: v8:7786
Cq-Include-Trybots: luci.chromium.try:linux_chromium_rel_ng
Change-Id: I0758bf6e431bf6e617244741ab2e1583a3566b20
Reviewed-on: https://chromium-review.googlesource.com/1140295Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Commit-Queue: Dan Elphick <delphick@chromium.org>
Cr-Commit-Position: refs/heads/master@{#54493}