Extend the current OOB support for typed arrays to also handle the
negative integer indices in the fast-path. This is safe because in
ECMAScript we never look up integer indexed properties (including
negative indices) on typed arrays in the prototype chain.

This reduces the performance cliff shown in the benchmark on the
relevant bug from

  console.timeEnd: Runtime deopt, 596.185000
  console.timeEnd: Runtime deopt, 1444.289000
  console.timeEnd: Runtime deopt, 1445.191000
  console.timeEnd: Runtime deopt, 1443.008000

to

  console.timeEnd: Runtime deopt, 590.017000
  console.timeEnd: Runtime deopt, 784.899000
  console.timeEnd: Runtime deopt, 792.428000
  console.timeEnd: Runtime deopt, 786.740000

which corresponds to a 2x improvement overall. It's not for free,
especially not in this benchmark, but the cliff isn't as bad as
it was previously.

Bug: v8:7027
Change-Id: Icf8a7ee87bb7ebc54f82c1b9166fc5e78c12bc0e
Cq-Include-Trybots: master.tryserver.chromium.linux:linux_chromium_rel_ng
Reviewed-on: https://chromium-review.googlesource.com/911574Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Commit-Queue: Benedikt Meurer <bmeurer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#51222}