glsl/shader_enums: Add the other two compute builtins

These weren't added before because they are actually calculated values that
are computed from other inputs.  However, in order to handle them in
nir_lower_system_values, it's nice for them to have a cannonical locaiton.

Reviewed-by: Rob Clark <robdclark@gmail.com>

src/compiler/shader_enums.c

@@ -215,6 +215,8 @@ gl_system_value_name(gl_system_value sysval)
      ENUM(SYSTEM_VALUE_TESS_LEVEL_OUTER),
      ENUM(SYSTEM_VALUE_TESS_LEVEL_INNER),
      ENUM(SYSTEM_VALUE_LOCAL_INVOCATION_ID),
+     ENUM(SYSTEM_VALUE_LOCAL_INVOCATION_INDEX),
+     ENUM(SYSTEM_VALUE_GLOBAL_INVOCATION_ID),
      ENUM(SYSTEM_VALUE_WORK_GROUP_ID),
      ENUM(SYSTEM_VALUE_NUM_WORK_GROUPS),
      ENUM(SYSTEM_VALUE_VERTEX_CNT),