Performance and stability improvements on all platforms.

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

Change-Id: I23dcb71373111ee81c3444e733647f1b231bca06
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1619661
Reviewed-by: v8-ci-autoroll-builder <v8-ci-autoroll-builder@chops-service-accounts.iam.gserviceaccount.com>
Cr-Commit-Position: refs/heads/7.6.220@{#1}
Cr-Branched-From: 437d710fc51e7e485bac8fd056c689a10d48a73d-refs/heads/master@{#61657}