GDScript: Revert multiple GDScriptCache related PRs

[dalexeev]

See #95076 (comment).

• Closes Severe performance regression when loading many GDScript files #95076.

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• Reopens GDScript doesn't recognize some newly added members until editor restart #76383.
• Reopens Type checking won't update when superclass is changed on type #81292.
• Probably reopens False error "Parse Error: The function signature doesn't match the parent." thrown in larger projects after changing both parent and child. #93347.
• Should not reopen issues fixed by #93166.

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• Reverts GDScript: Fix common mismatched external parser errors (second try) #94871.
• Reverts GDScriptCache: Clear abandoned parser refs #94678.
• Reverts GDScript: Invalidate cached parser chain when reloading #92616.
• Reverts Fix mismatched external parser with binary exports #93166.
• Reverts GDScript: Fix out of date errors in depended scripts #90601.

[mihe]

I can confirm that this fixes the regression reported in #95076, and results in a memory timeline much like what was seen prior to #92616, at 9db1a96.

[akien-mga]

Superseded by #95115, for now 🤞