Bytecodes used by the regular expression interpreter often occur in
specific sequences. The number of dispatches in the interpreter can be
reduced if those sequences are combined into a single bytecode.

This CL adds a peephole optimization pass for regexp bytecodes.
This pass checks the generated bytecode for pre-defined sequences that
can be merged into a single bytecode.

With the currently implemented bytecode sequences a speedup of 1.12x on
regex-dna and octane-regexp is achieved.

Bug: v8:9330
Change-Id: I827f93273a5848e5963c7e3329daeb898995d151
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1813743
Commit-Queue: Patrick Thier <pthier@google.com>
Reviewed-by: Peter Marshall <petermarshall@chromium.org>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Cr-Commit-Position: refs/heads/master@{#63992}