Before this we were using String.prototype.replace. Now
we call the internal StringReplace instead.

BUG=v8:4221
LOG=N
R=adamk, littledan
CQ_INCLUDE_TRYBOTS=tryserver.chromium.linux:linux_chromium_rel_ng;tryserver.blink:linux_blink_rel

Review URL: https://codereview.chromium.org/1199933005

Cr-Commit-Position: refs/heads/master@{#29206}