String.prototype[Symbol.iterator] does RequireObjectCoercible(this) (issue 4348).

Stage restrictive declarations flag (issue 4824).

Expose Array.prototype.values behind a flag and stage it (issue 4247).

Performance and stability improvements on all platforms.

Cr-Commit-Position: refs/heads/5.1.95@{#1}
Cr-Branched-From: 0f8cb27ef0fb56a63901755ed32a532aca62874f-refs/heads/master@{#34649}