gc-stress failure believed to have been fixed in:
https://crrev.com/6a806a558158cbab55ad9a1a456942a7c509c810

BUG= https://code.google.com/p/v8/issues/detail?id=4203
TEST=mjsunit/wasm/embenchen
R=aseemgarg@chromium.org,titzer@chromium.org
LOG=N

Review URL: https://codereview.chromium.org/1827813006

Cr-Commit-Position: refs/heads/master@{#35063}