Issue #26647: Fix typo in test_grammar

Patch written by Demur Rumed.

Lib/test/test_grammar.py

@@ -994,7 +994,7 @@ class GrammarTests(unittest.TestCase):
         # Test ifelse expressions in various cases
         def _checkeval(msg, ret):
             "helper to check that evaluation of expressions is done correctly"
-            print(x)
+            print(msg)
             return ret
 
         # the next line is not allowed anymore