Character class handling in the irregexp pipeline is quite complex;
codepoints outside the BMP (basic multilingual plane) are only
translated into surrogate pairs when needed, e.g. when the subject
string is two-byte. If not needed, the codepoints simply stay part of
the list of CharacterRanges.

In EmitCharClass, we determine the valid subset of ranges through
ranges_length; until this CL, we forgot to pass that information on to
MakeRangeArray. Do that now by truncating the list of CharacterRanges.

Fixed: chromium:1262423
Change-Id: I5bb5b839e9935890ca2d10908ad66d72c3217178
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3240782
Commit-Queue: Jakob Gruber <jgruber@chromium.org>
Auto-Submit: Jakob Gruber <jgruber@chromium.org>
Reviewed-by: Mathias Bynens <mathias@chromium.org>
Cr-Commit-Position: refs/heads/main@{#77514}