Revert "Clean up SkSL inliner and allow it to be disabled."

This reverts commit d34d56e2791cd859a4eee60719a4f1071c7a3a5c.

Reason for revert: Pinpoint

This is not a pure rollback (we keep the early-out checks for
fInlineThreshold to avoid breaking tests).

Original change's description:
> Clean up SkSL inliner and allow it to be disabled.
>
> - When fInlineThreshold is zero, the inliner doesn't need to run at all.
> - Inlining functionality outside of `analyze` can be made private now;
>   it's not referenced by the IRGenerator any more.
>
> Change-Id: If61fd8998bc024201bf4489b7aa48ac4d117e449
> Reviewed-on: https://skia-review.googlesource.com/c/skia/+/325617
> Auto-Submit: John Stiles <johnstiles@google.com>
> Reviewed-by: Brian Osman <brianosman@google.com>
> Commit-Queue: John Stiles <johnstiles@google.com>

TBR=brianosman@google.com,ethannicholas@google.com,johnstiles@google.com

Change-Id: I288d82273abfc2587859cc92d5a4c663694c38a4
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/325621
Commit-Queue: John Stiles <johnstiles@google.com>
Reviewed-by: John Stiles <johnstiles@google.com>
2 files changed