Cleanup of shader building system

Cleanup of shader building system

this is a huge refactor and cleanup of the gl shader building system in
Skia.  The entire shader building pipeline is now part of
GrGLProgramCreator, which takes a gp, and some fps, and creates a
program.  I added some subclasses of GrGLProgram to handle the
eccentricities of Nvpr/Nvpres.  Outside of the builders folder
and GrGLPrograms, this change is basically just a rename

solo gp

BUG=skia:

Committed: https://skia.googlesource.com/skia/+/fe1233c3f12f81bb675718516bbb32f72af726ec

Review URL: https://codereview.chromium.org/611653002