Properly check GLX_INDIRECT_RENDERING in glapi/tests/check_table

Actually use $DEFINES, so we can see if GLX_INDIRECT_RENDERING is defined

If GLX_INDIRECT_RENDERING is defined,  _GLAPI_SKIP_PROTO_ENTRY_POINTS will
be defined, and libglapi won't contain the 'protocol entry points', so we
should provide stubs in check_table.cpp

src/mapi/glapi/tests/check_table.cpp

@@ -1511,7 +1511,7 @@ const struct name_offset known_dispatch[] = {
    { NULL, 0 }
 };
 
-#ifndef GLX_INDIRECT_RENDERING
+#ifdef GLX_INDIRECT_RENDERING
 extern "C" {
 GLAPI GLboolean GLAPIENTRY
 glAreTexturesResidentEXT(GLsizei n, const GLuint *textures,