Performance and stability improvements on all platforms.

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

Change-Id: I5bf024d32dd90a2c534e12302642fec93aa9e916
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1611837
Reviewed-by: v8-ci-autoroll-builder <v8-ci-autoroll-builder@chops-service-accounts.iam.gserviceaccount.com>
Cr-Commit-Position: refs/heads/7.6.177@{#1}
Cr-Branched-From: 23834cbdfd50af82d436b8d59a44b0ce004310aa-refs/heads/master@{#61473}