This reduces the overhead of calling the builtin.
Quick measurements show >5x improvement. As the
typed array's size grows, iterating dominates
and the performance gap closes.
https://github.com/peterwmwong/v8-perf/blob/master/typedarray-findIndex/README.md

Bug: v8:5929
Change-Id: I27d67776c83cbe28f4f9f5ef479a7eeabf594654
Reviewed-on: https://chromium-review.googlesource.com/792394
Commit-Queue: Jakob Gruber <jgruber@chromium.org>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Cr-Commit-Position: refs/heads/master@{#49720}