Performance and stability improvements on all platforms.

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

Change-Id: I49e961712bc730ccc8dfe61fa541a7648f94b7fb
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1593099
Reviewed-by: v8-ci-autoroll-builder <v8-ci-autoroll-builder@chops-service-accounts.iam.gserviceaccount.com>
Cr-Commit-Position: refs/heads/7.6.86@{#1}
Cr-Branched-From: 01821ab3b6d9108572ca564801e13ceccf17e1e5-refs/heads/master@{#61151}