Add SPIR-V test for matrix-op-scalar math.

This is a clone of the Metal test. (This can be moved into shared/ and
enabled as a real test once the codegen is fixed.)

At present, this test generates broken code; everything is writing an
SpvOpMatrixTimesScalar opcode regardless of the actual operation being
performed.

Change-Id: If06b4196e7d9be36e41c5c60c006b2a713cc25d8
Bug: skia:11985
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/408297
Auto-Submit: John Stiles <johnstiles@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>
3 files changed