This reverts commit f45045cc.

Reason for revert: <INSERT REASONING HERE>

Original change's description:
> [parser] Move some PPSD sanity checks to debug
> 
> Move some of PreParsedScopeData's santity checks, such as the magic
> value separating skippable function data from scope data, to be debug
> only, to save memory.
> 
> Start position of inner skippable functions is still kept, because it's
> too good at catching bugs, but we may want to remove it in the future
> as well.
> 
> Bug: chromium:818642
> Change-Id: If86ff1b9845e8dd3b015b4e554d0033328b145bf
> Reviewed-on: https://chromium-review.googlesource.com/1127046
> Commit-Queue: Leszek Swirski <leszeks@chromium.org>
> Reviewed-by: Marja Hölttä <marja@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#54263}

TBR=marja@chromium.org,leszeks@chromium.org

Change-Id: I15ceedd66d9ecb66cf65f5834d09975b41d3ed27
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: chromium:818642
Reviewed-on: https://chromium-review.googlesource.com/1127859Reviewed-by: Sigurd Schneider <sigurds@chromium.org>
Commit-Queue: Sigurd Schneider <sigurds@chromium.org>
Cr-Commit-Position: refs/heads/master@{#54290}