Otherwise (this) will leak into a later this=> making it seem like a valid
arrow function head.

Bug: chromium:941703
Change-Id: I5c3ff70f1d525ec0da53b401a0bfec4c1ee7812f
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1601260
Commit-Queue: Toon Verwaest <verwaest@chromium.org>
Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Cr-Commit-Position: refs/heads/master@{#61345}