Revert "remove sksl interpreter guards"

This reverts commit 7f1117e88611a9df157864884bb55040aa65867d.

Reason for revert: Seems like Clang gets stuck allocating registers on ARM,

[2477/38027] CXX obj/skia/skia/SkSLByteCode.o
FAILED: obj/skia/skia/SkSLByteCode.o
/b/s/w/ir/cache/goma/client/gomacc ../../third_party/llvm-build/Release+Asserts/bin/clang++ -MMD -MF...(too long)
fatal error: error in backend: Error while trying to spill LR from class GPR: Cannot scavenge register without an emergency spill slot!
PLEASE submit a bug report to https://crbug.com and run tools/clang/scripts/process_crashreports.py (only works inside Google) which will upload a report and include the crash backtrace, preprocessed source, and associated run script.
Stack dump:
0.	Program arguments: ../../third_party/llvm-build/Release+Asserts/bin/clang++ -MMD -MF obj/skia/ski...(too long)


Original change's description:
> remove sksl interpreter guards
> 
> This is only used by particles, benchmarks, and tests,
> and should be swept away by dead code elimination otherwise.
> 
> Change-Id: I10462d6ae0a08dd8219fc49325160ec6790632af
> Reviewed-on: https://skia-review.googlesource.com/c/skia/+/311759
> Reviewed-by: Brian Osman <brianosman@google.com>
> Commit-Queue: Mike Klein <mtklein@google.com>

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

Change-Id: I1b6370d39285210267425f090235a4d80aebe4fa
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/312034
Reviewed-by: Mike Klein <mtklein@google.com>
Commit-Queue: Mike Klein <mtklein@google.com>
9 files changed