Add fast paths when RegExp and RegExp result are fast wherever possible.

As shown below, this CL improves the performance of calling S.p.matchAll and
iterating over matches.

Before:

StringMatchAllBuiltinRegExpIteratorCreation-Strings(Score): 5002
StringMatchAllBuiltinStringIteratorCreation-Strings(Score): 13798
StringMatchAllBuiltinString-Strings(Score): 197
StringMatchAllManualString-Strings(Score): 454
StringMatchAllBuiltinRegExp-Strings(Score): 193
StringMatchAllManualRegExp-Strings(Score): 453
StringMatchAllBuiltinZeroWidth-Strings(Score): 97.2
StringMatchAllBuiltinZeroWidthUnicode-Strings(Score): 95.9

After:

StringMatchAllBuiltinRegExpIteratorCreation-Strings(Score): 15437
StringMatchAllBuiltinStringIteratorCreation-Strings(Score): 16708
StringMatchAllBuiltinString-Strings(Score): 392
StringMatchAllManualString-Strings(Score): 452
StringMatchAllBuiltinRegExp-Strings(Score): 394
StringMatchAllManualRegExp-Strings(Score): 484
StringMatchAllBuiltinZeroWidth-Strings(Score): 409
StringMatchAllBuiltinZeroWidthUnicode-Strings(Score): 413

Bug: v8:6890
Change-Id: I6fcc1003a471314cf412aac456d42286b2926810
Reviewed-on: https://chromium-review.googlesource.com/1005400
Commit-Queue: Peter Wong <peter.wm.wong@gmail.com>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Cr-Commit-Position: refs/heads/master@{#52581}