glsl: Implement all(v) as all_equal(v, true).
glsl: Implement all(v) as all_equal(v, true).

Reviewed-by: Ian Romanick <2b237cafb16dc45038e85df6c85e74e6d899eba9@intel.com>

metora/MesaGLSLCompiler,metora/MesaGLSLCompiler,metora/MesaGLSLCompiler