Remove unused kTexture2D_GrSLType and kSampler_GrSLType

Also remove unused GrSLTypeIs2DCombinedSamplerType

Bug: skia:
Change-Id: I9c670535dbbc30ddeb3636acb5b784580a968ee4
Reviewed-on: https://skia-review.googlesource.com/144035
Commit-Queue: Brian Salomon <bsalomon@google.com>
Reviewed-by: Greg Daniel <egdaniel@google.com>
4 files changed