This is a reland of 0d91db0b.

Proposal repository:
https://github.com/tc39/proposal-well-formed-stringify

Intent to ship:
https://groups.google.com/d/msg/v8-users/IRu3bAC_pLM/pFwz2ti1AgAJ

TBR=gsathya@chromium.org

Bug: v8:7782
Change-Id: I53d006650e2b4099a111d2e5bc067e4a2c7cf4a0
Reviewed-on: https://chromium-review.googlesource.com/c/1282993Reviewed-by: Mathias Bynens <mathias@chromium.org>
Commit-Queue: Mathias Bynens <mathias@chromium.org>
Cr-Commit-Position: refs/heads/master@{#56689}