- Eliminates non-const reference parameters in src/objects.

Bug: v8:9429
Change-Id: Ic39a59d54bda26c622db29f07143055c3cc6c7a0
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1794683Reviewed-by: Clemens Hammacher <clemensh@chromium.org>
Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Commit-Queue: Bill Budge <bbudge@chromium.org>
Cr-Commit-Position: refs/heads/master@{#63650}