FIx unnecessary generic shader permutations

[VReaperV]

NUKE the GENERIC_2D macro and add trGlobals_t::skipSubgroupProfiler to skip the subgroup profiler instead.

Alternative to #1486.

[illwieckz]

• with Merge generic2D shader into generic #1483
  built 341 glsl shaders in 3488 msec
• with Revert "Merge generic2D shader into generic" #1486
  built 324 glsl shaders in 3129 msec
• with this:
  built 323 glsl shaders in 3200 msec

[illwieckz]

LGTM.