Performance and stability improvements on all platforms.

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

Change-Id: I57af717a21e47063370324c3432bb50146c49134
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1588994
Reviewed-by: v8-ci-autoroll-builder <v8-ci-autoroll-builder@chops-service-accounts.iam.gserviceaccount.com>
Cr-Commit-Position: refs/heads/7.6.65@{#1}
Cr-Branched-From: 57b30632d8b7e5ba6d063184030bc2308ab280ae-refs/heads/master@{#61099}