Correct typo in comment

Author: Thomas Kiley

regression/validate-trace-xml-schema/check.py

@@ -12,7 +12,7 @@
 
 # some tests in the cbmc suite don't work for the trace checks for one reason or another
 ExcludedTests = list(map(lambda s: os.path.join(test_base_dir, s), [
-    # these tests except input from stdin
+    # these tests expect input from stdin
     'json-interface1/test_wrong_option.desc',
     'json-interface1/test.desc',
     'json-interface1/test_wrong_flag.desc',