This reverts commit a7607221.

Reason for revert: fails on GC Stress bot:
https://ci.chromium.org/ui/p/v8/builders/ci/V8%20Linux%20-%20gc%20stress/38512/overview

Original change's description:
> Disable recompilation of existing Scripts from Isolate compilation cache
>
> My previous change https://crrev.com/c/3597106 led to some performance
> regressions in time spent on parsing and compilation. This change
> disables the ability to recompile an existing uncompiled Script, as an
> attempt to both fix the regressions and isolate which part of the
> previous change was the cause of those problems.
>
> Bug: v8:12808, chromium:1325566, chromium:1325567, chromium:1325601
> Change-Id: Ifa086bf27070da8f4b3c0e4415af5ca7b6706b0a
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3652252
> Reviewed-by: Leszek Swirski <leszeks@chromium.org>
> Commit-Queue: Seth Brenith <seth.brenith@microsoft.com>
> Cr-Commit-Position: refs/heads/main@{#80616}

Bug: v8:12808, chromium:1325566, chromium:1325567, chromium:1325601
Change-Id: I0f56163856d04ff49da96b0fb344fb59b5501a40
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3653273
Auto-Submit: Adam Klein <adamk@chromium.org>
Commit-Queue: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Cr-Commit-Position: refs/heads/main@{#80617}