Performance and stability improvements on all platforms.

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

Change-Id: I34f06c8a719b5301ded613ac5794bc21e1b95012
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1630743
Reviewed-by: v8-ci-autoroll-builder <v8-ci-autoroll-builder@chops-service-accounts.iam.gserviceaccount.com>
Cr-Commit-Position: refs/heads/7.6.292@{#1}
Cr-Branched-From: f71cba999fa8d8bda33c746dcbaede37465f6bd2-refs/heads/master@{#61868}