We used to serialize the full source code of the script being
serialized. This CL makes the source code maximally minimal (only
including the needed outer functions) while maintaining the "inner
function is textually inside its outer function" relationship.

Bug: v8:11525
Change-Id: Ic42772f7ecb76744bc11b97fa1784d847558e1f6
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3401864Reviewed-by: Camillo Bruni <cbruni@chromium.org>
Commit-Queue: Marja Hölttä <marja@chromium.org>
Cr-Commit-Position: refs/heads/main@{#78716}