This saves about 10% time in the initial copy of standard objects
in the TypeScript benchmark.

Bug: v8:7790
Change-Id: I2e725d43972db9598285f84fbba3c167cf8716b7
Reviewed-on: https://chromium-review.googlesource.com/1235657
Commit-Queue: Jaroslav Sevcik <jarin@chromium.org>
Reviewed-by: Maya Lekova <mslekova@chromium.org>
Reviewed-by: Georg Neis <neis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#56080}