mesa: Store gl_shader_stage enum in gl_shader objects.

Reviewed-by: Brian Paul <brianp@vmware.com>
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>

src/glsl/test_optpass.cpp

@@ -204,6 +204,7 @@ int test_optpass(int argc, char **argv)
 
    struct gl_shader *shader = rzalloc(NULL, struct gl_shader);
    shader->Type = shader_type;
+   shader->Stage = _mesa_shader_enum_to_shader_stage(shader_type);
 
    string input = read_stdin_to_eof();