Performance and stability improvements on all platforms.

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

Change-Id: I10d043b8dc6e1405ef0c508882c056cb83452a45
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1582001
Reviewed-by: v8-ci-autoroll-builder <v8-ci-autoroll-builder@chops-service-accounts.iam.gserviceaccount.com>
Cr-Commit-Position: refs/heads/7.6.16@{#1}
Cr-Branched-From: de93b80815c2e5fcbea2ea308697a936fa14a416-refs/heads/master@{#60973}