st/mesa: don't dirty sample shading on _NEW_PROGRAM
st/mesa: don't dirty sample shading on _NEW_PROGRAM

Already done as part of ST_NEW_FRAGMENT_PROGRAM in st_validate_state.

Reviewed-by: Nicolai Hähnle <0d0be6cf5ad662651be2dc5dfd44aa2b09d4c1cc@amd.com>

metora/MesaGLSLCompiler,metora/MesaGLSLCompiler,metora/MesaGLSLCompiler