There's no need to set it so early - it's only needed when the function has
really been parsed. This way we don't need to produce and store it for skipped
inner functions.

BUG=v8:5516

Change-Id: Ida2abd44b494030771b5663a8eb326edb0a53b72
Reviewed-on: https://chromium-review.googlesource.com/461160Reviewed-by: Toon Verwaest <verwaest@chromium.org>
Commit-Queue: Marja Hölttä <marja@chromium.org>
Cr-Commit-Position: refs/heads/master@{#44235}