avoid useless indirection for module dict lookup and instead use known reference directly

Cython/Utility/Builtins.c

@@ -99,9 +99,7 @@ static PyObject* __Pyx_PyExec3(PyObject* o, PyObject* globals, PyObject* locals)
     char *code = 0;
 
     if (!globals || globals == Py_None) {
-        globals = PyModule_GetDict($module_cname);
-        if (!globals)
-            goto bad;
+        globals = $moddict_cname;
     } else if (!PyDict_Check(globals)) {
         PyErr_Format(PyExc_TypeError, "exec() arg 2 must be a dict, not %.200s",
                      Py_TYPE(globals)->tp_name);

Cython/Utility/Exceptions.c

@@ -514,12 +514,10 @@ static void __Pyx_AddTraceback(const char *funcname, int c_line,
         if (!py_code) goto bad;
         $global_code_object_cache_insert(c_line ? c_line : py_line, py_code);
     }
-    py_globals = PyModule_GetDict($module_cname);
-    if (!py_globals) goto bad;
     py_frame = PyFrame_New(
         PyThreadState_GET(), /*PyThreadState *tstate,*/
         py_code,             /*PyCodeObject *code,*/
-        py_globals,          /*PyObject *globals,*/
+        $moddict_cname,      /*PyObject *globals,*/
         0                    /*PyObject *locals*/
     );
     if (!py_frame) goto bad;