glsl: store subroutine remap table in shader cache
glsl: store subroutine remap table in shader cache

V2: use new helpers to store/restore table entries.

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

metora/MesaGLSLCompiler,metora/MesaGLSLCompiler,metora/MesaGLSLCompiler