Performance and stability improvements on all platforms.

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

Change-Id: I3a819d490a3cf4b91d5e6b4d6f02c4cde0bd7e2a
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1584225
Reviewed-by: v8-ci-autoroll-builder <v8-ci-autoroll-builder@chops-service-accounts.iam.gserviceaccount.com>
Cr-Commit-Position: refs/heads/7.6.38@{#1}
Cr-Branched-From: eeb8ac685d02590579eb48e25cc407a8fe5d854c-refs/heads/master@{#61018}