- Expose fast paths for RegExpPrototypeMatchBody/RegExpPrototypeSearchBody as TFS builtins
- Add StringPrototypeMatch and StringPrototypeSearch TFJ builtins
  - Add StringMatchSearchAssembler to ensure same search/match behavior
- Remove functionality from string.js

A quick benchmark shows gains of 20-30% for unoptimized code and 0-20% for optimized code.
https://github.com/peterwmwong/v8-perf/blob/master/string-search-match/README.md

Bug: v8:5049
Change-Id: I0fffee6e94e62ecae049c9e5798da52d67ae1823
Reviewed-on: https://chromium-review.googlesource.com/707824
Commit-Queue: Jakob Gruber <jgruber@chromium.org>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48452}