The flag in question was on by defautl for a while now and has never
been supported for optimized code generated from bytecode. We no longer
support eliding stack-checks within loops just in optimized code.

R=bmeurer@chromium.org
BUG=v8:5653

Review-Url: https://codereview.chromium.org/2643773008
Cr-Commit-Position: refs/heads/master@{#42574}