gh-128217: Validate the normalized_environment variable instead of the similarly named function (GH-128220)

Author: smurav

Modules/_winapi.c

@@ -1048,7 +1048,7 @@ getenvironment(PyObject* environment)
     }
 
     normalized_environment = normalize_environment(environment);
-    if (normalize_environment == NULL) {
+    if (normalized_environment == NULL) {
         return NULL;
     }