This CL implements the upcoming spec change:
https://github.com/tc39/proposal-regexp-match-indices/pull/49

A new JSRegExpResultWithIndices subclass is introduced with a separate map and
an extra slot for storing the indices. If /d is passed, exec() constructs a
JSRegExpResultWithIndices and eagerly builds indices.

The existing re-execution logic is removed.

Bug: v8:9548
Change-Id: Ic11853e7521017af5e8bd583c7b82bb672821132
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2616873
Commit-Queue: Shu-yu Guo <syg@chromium.org>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Reviewed-by: Toon Verwaest <verwaest@chromium.org>
Cr-Commit-Position: refs/heads/master@{#72306}