Revert "SkSLInterpreter refactoring"

This reverts commit 2cfc6b3020f5544f010e347742a0fecf81786f2a.

Reason for revert: ASAN issue

Original change's description:
> SkSLInterpreter refactoring
> 
> A zillion little refactors:
> 
>   - small implementation simplifications all over,
>     dead code removal, singleton code inlining,
>     macro -> lambda, etc.
> 
>   - copy args to stack in outer run(),
>     which is where we copy from stack to args.
> 
>   - scope temporaries more closely to the switch
>     cases that use them rather than to all of run()
> 
>   - vertically align analogous cases,
>     especially fall through
> 
> Change-Id: I7694b85724500717e6015bf7600f125c83a0d408
> Reviewed-on: https://skia-review.googlesource.com/c/skia/+/214900
> Commit-Queue: Mike Klein <mtklein@google.com>
> Reviewed-by: Ethan Nicholas <ethannicholas@google.com>

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

Change-Id: I88046e0c2a67ab8d599597da00e81f3f004f8791
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/215000
Reviewed-by: Chris Dalton <csmartdalton@google.com>
Commit-Queue: Chris Dalton <csmartdalton@google.com>
2 files changed