Performance and stability improvements on all platforms.

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

Change-Id: I574432824a9f10e027894f718b41fe75408f5366
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1619152
Reviewed-by: v8-ci-autoroll-builder <v8-ci-autoroll-builder@chops-service-accounts.iam.gserviceaccount.com>
Cr-Commit-Position: refs/heads/7.6.214@{#1}
Cr-Branched-From: b2d0d24ea9f49b02371c0495444081d03c7d4f00-refs/heads/master@{#61635}