Performance and stability improvements on all platforms.

TBR=v8-ci-autoroll-builder@chops-service-accounts.iam.gserviceaccount.com

Change-Id: I35ed7832e708c7cbb5986cb8612c09b5ada73924
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1550708
Reviewed-by: v8-ci-autoroll-builder <v8-ci-autoroll-builder@chops-service-accounts.iam.gserviceaccount.com>
Cr-Commit-Position: refs/heads/7.5.176@{#1}
Cr-Branched-From: a330f15b698e66d22e7ae99fb1eddc54c150fff7-refs/heads/master@{#60606}