This fixes simulated debug-mode failures in the following tests:
  mjsunit/regexp-stack-overflow
  mjsunit/regress/regress-crbug-467047

R=mbrandy@us.ibm.com

BUG=

Review URL: https://codereview.chromium.org/1035003002

Cr-Commit-Position: refs/heads/master@{#27500}