Performance and stability improvements on all platforms.

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

Change-Id: I14c18a6422de78e0a3e77426c1b5f462e6dfac39
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1625091
Reviewed-by: v8-ci-autoroll-builder <v8-ci-autoroll-builder@chops-service-accounts.iam.gserviceaccount.com>
Cr-Commit-Position: refs/heads/7.6.258@{#1}
Cr-Branched-From: 1f0543af7a96ef09ed92e9ef8d99277c24492c3c-refs/heads/master@{#61740}