Only use GrRenderTarget for sample locations in GrGLSLProgramBuilder

The idea here is to separate information we can have at opList time:
   numSamples, origin, primProc, primProcProxies and pipeline
and what we can only have at flush time:
   sample locations

The opList-available parameters will then be moved into a descriptor (GrProgramInfo).

Change-Id: Iae044a98a0cfc8685569c923d154a6f9dabfeb75
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/245621
Reviewed-by: Greg Daniel <egdaniel@google.com>
Commit-Queue: Robert Phillips <robertphillips@google.com>
26 files changed