systemc: Record the test's return code in the output directory.

verify.py will be able to use that value later to determine whether a
test was successful.

Change-Id: Ib499a4b6f202ee46e66e5de1b61a7e6309df9886
Reviewed-on: https://gem5-review.googlesource.com/12052
Reviewed-by: Gabe Black <gabeblack@google.com>
Maintainer: Gabe Black <gabeblack@google.com>

src/systemc/tests/verify.py

@@ -144,7 +144,14 @@ class RunPhase(TestPhaseBase):
                 '--listener-mode=off',
                 config_path
             ])
-            subprocess.check_call(cmd)
+            try:
+                subprocess.check_call(cmd)
+            except subprocess.CalledProcessError, error:
+                returncode = error.returncode
+            else:
+                returncode = 0
+            with open(os.path.join(test.m5out_dir(), 'returncode'), 'w') as rc:
+                rc.write('%d\n' % returncode)
 
         runnable = filter(lambda t: not t.compile_only, tests)
         if args.j == 1: