Revert "Add SkSLCompiler::toHLSL, using SPIRV-Cross"

This reverts commit cf7c7e38e8adf62e88945b5ae0b40b05c38e8afe.

Reason for revert: Breaking our Flutter build.

Original change's description:
> Add SkSLCompiler::toHLSL, using SPIRV-Cross
> 
> Change-Id: Ia7a11a726cac006f6acc36efe8fc2ff27f30af72
> Reviewed-on: https://skia-review.googlesource.com/c/skia/+/270837
> Reviewed-by: Brian Salomon <bsalomon@google.com>
> Commit-Queue: Brian Osman <brianosman@google.com>

TBR=jvanverth@google.com,bsalomon@google.com,brianosman@google.com,ethannicholas@google.com

Change-Id: I2a1353864e2225578271573a8f7157d95fb0c969
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/271744
Reviewed-by: Brian Osman <brianosman@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>
7 files changed