V8 uses a backtracking regexp engine, which has the caveat that some
regexp patterns can have exponential runtime behavior when excessive
backtracking is involved.

Especially when regexp patterns are user-controlled, it would be useful
to be able to set an upper limit for a single regexp execution. This CL
takes an initial step in that direction by adding a backtracking limit
(intended to approximate execution time):

- The limit is stored in the JSRegExp's data array.
- A limit can currently only be set through the %NewRegExpWithLimit
runtime function.
- The limit is applied during interpreter execution. When exceeded, the
interpreter stops execution and returns FAILURE (even if continued
execution would at some later point have resulted in SUCCESS).

In follow-up CLs, this mechanism will be extended to work in jitted
regexp code, and exposed through the V8 API.

Bug: v8:9695
Change-Id: Iadb5c100052f4a63b26f1ec49cf97c6713a66b9b
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1864934
Commit-Queue: Ulan Degenbaev <ulan@chromium.org>
Auto-Submit: Jakob Gruber <jgruber@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Reviewed-by: Peter Marshall <petermarshall@chromium.org>
Cr-Commit-Position: refs/heads/master@{#64417}