GC performance issues need to be addressed first.

TBR=bmeurer@chromium.org, mstarzinger@chromium.org, yangguo@chromium.org
BUG=v8:5456

Review-Url: https://codereview.chromium.org/2642743002
Cr-Original-Commit-Position: refs/heads/master@{#42495}
Committed: https://chromium.googlesource.com/v8/v8/+/7803aa1ffb2f835c5f317ed2a097390d53e52567
Review-Url: https://codereview.chromium.org/2642743002
Cr-Commit-Position: refs/heads/master@{#42517}