This improves the performance on primitive strings of
IterableToListWithSymbolLookup, which implements the
CreateArrayFromIterable bytecode. The fast path is only
taken if the string iterator protector is valid (that is,
String.prototype[Symbol.iterator] and
String.prototype[Symbol.iterator]().next are untouched).

This brings spreading of primitive strings closer to the
performance of the string iterator optimizations.
(see https://docs.google.com/document/d/13z1fvRVpe_oEroplXEEX0a3WK94fhXorHjcOMsDmR-8/).

Bug: chromium:881273, v8:7980
Change-Id: Ic8d8619da2f2afcc9346203613a844f62653fd7a
Reviewed-on: https://chromium-review.googlesource.com/1243110
Commit-Queue: Hai Dang <dhai@google.com>
Reviewed-by: Georg Neis <neis@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Reviewed-by: Benedikt Meurer <bmeurer@chromium.org>
Reviewed-by: Sigurd Schneider <sigurds@chromium.org>
Cr-Commit-Position: refs/heads/master@{#56329}