Actually die if a parallel test fails.

bin/cros_au_test_harness.py

Index: bin/cros_au_test_harness.py
diff --git a/bin/cros_au_test_harness.py b/bin/cros_au_test_harness.py
index b9578a28eb7f3412446a3e8e3d43389aae18e032..47d51ad29ec24b5d2cc4925f0b3ad02ccbc39ab5 100755
--- a/bin/cros_au_test_harness.py
+++ b/bin/cros_au_test_harness.py
@@ -912,8 +912,9 @@ def _RunTestsInParallel(parser, options, test_class):
     args.append(test_case)
 
   results = _RunParallelJobs(options.jobs, threads, args, print_status=False)
-  if not (test_result.wasSuccessful() for test_result in results):
-    Die('Test harness was not successful')
+  for test_result in results:
+    if not test_result.wasSuccessful():
+      Die('Test harness was not successful')
 
 
 def main():