This reverts commit 97ead433.

Reason for revert: makes the PreParserScopeAnalysis test much slower.

Original change's description:
> [parser] Skipping inner funcs: Use less memory for variables.
> 
> - Make it possible to store quarter-bytes instead of full bytes.
> 
> - Don't store is_used; it can be recovered correctly based on the actual full
>   parse (when a lazy function is eventually called) and
>   has_forced_scope_allocation.
> 
> - With the is_used change, the old testing approach (which compared a scope for
>   which we didn't do scope allocation to the baseline) no longer made
>   sense. Replaced it with a new testing approach, which is also closer to the
>   actual usage.
> 
> BUG=v8:5516
> 
> Change-Id: I02bac24e482126689dcdbabe8b3a04977be29b0c
> Reviewed-on: https://chromium-review.googlesource.com/725422
> Commit-Queue: Marja Hölttä <marja@chromium.org>
> Reviewed-by: Toon Verwaest <verwaest@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#48828}

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

Change-Id: I8cb87bcd55462b1cef4444dabb5cbfa2ecb24c7c
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: v8:5516
Reviewed-on: https://chromium-review.googlesource.com/732878Reviewed-by: Marja Hölttä <marja@chromium.org>
Commit-Queue: Marja Hölttä <marja@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48829}