Performance and stability improvements on all platforms.

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

Change-Id: Id1f2cece222a1dd58be92a329a3f50574d4a59b5
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1627574
Reviewed-by: v8-ci-autoroll-builder <v8-ci-autoroll-builder@chops-service-accounts.iam.gserviceaccount.com>
Cr-Commit-Position: refs/heads/7.6.265@{#1}
Cr-Branched-From: 5cf05dca69123a4f019bac862d05d57e0ac289b8-refs/heads/master@{#61788}