Revert "Performance experiment: Disable SkSL optimization in nanobench/skpbench"

This reverts commit b34a896c12d8559db1b14425bd403f78e811fad7.

Reason for revert: experiment is complete

Original change's description:
> Performance experiment: Disable SkSL optimization in nanobench/skpbench
>
> Cloned from http://review.skia.org/369716
> Re-running the experiment now that @switch is supported when
> optimizations are disabled.
>
> Change-Id: I428051d9c679a8084589fba428a637f36587be16
> Bug: skia:11341
> Reviewed-on: https://skia-review.googlesource.com/c/skia/+/374516
> Commit-Queue: John Stiles <johnstiles@google.com>
> Reviewed-by: Brian Salomon <bsalomon@google.com>

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

Change-Id: I1e91c55538ef35f413f2c41c83df9d9c0f29d9a1
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: skia:11341
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/375016
Reviewed-by: John Stiles <johnstiles@google.com>
Commit-Queue: John Stiles <johnstiles@google.com>
3 files changed