Removes GetHeap/GetIsolate from FixedArray::Shrink and
FixedArray::SetAndGrow.

Bug: v8:7786
Cq-Include-Trybots: luci.chromium.try:linux_chromium_rel_ng
Change-Id: I8db2680f5ef69e901383e0b2cb60198c1b8dd316
Reviewed-on: https://chromium-review.googlesource.com/1131184Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Reviewed-by: Hannes Payer <hpayer@chromium.org>
Reviewed-by: Yang Guo <yangguo@chromium.org>
Commit-Queue: Dan Elphick <delphick@chromium.org>
Cr-Commit-Position: refs/heads/master@{#54373}