Revert "[M120-LTS][SkSL:RP] Prevent overflow when computing slot allocation size"

This reverts commit a59291ec277803d5b231b1a82ab2275e4823bd3f.

Reason for revert: unit test uses code not in m120.

Original change's description:
> [M120-LTS][SkSL:RP] Prevent overflow when computing slot allocation size
>
> Bug: 355465305
> Change-Id: Ife25289f7b3489701c67b7dc5d30e473019a1193
> Reviewed-on: https://skia-review.googlesource.com/c/skia/+/888376
> Commit-Queue: Brian Osman <brianosman@google.com>
> (cherry picked from commit d1b243ba90f0698ced6fadc460adb9d66c248946)
> Reviewed-on: https://skia-review.googlesource.com/c/skia/+/892676
> Reviewed-by: Michael Ludwig <michaelludwig@google.com>

Bug: 355465305
Change-Id: I27fe9fa6d769c84955bbbc2ca01c10305d4349b2
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/899717
Auto-Submit: Michael Ludwig <michaelludwig@google.com>
Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
3 files changed