If the timeout is exceeded, count the tests as skipped instead of just
issuing a warning.
diff --git a/Lib/test/test_signal.py b/Lib/test/test_signal.py
index 94ee4d1..228a776 100644
--- a/Lib/test/test_signal.py
+++ b/Lib/test/test_signal.py
@@ -431,9 +431,8 @@
             if signal.getitimer(self.itimer) == (0.0, 0.0):
                 break # sig_vtalrm handler stopped this itimer
         else: # Issue 8424
-            sys.stdout.write("test_itimer_virtual: timeout: likely cause: "
-                             "machine too slow or load too high.\n")
-            return
+            raise unittest.SkipTest("timeout: likely cause: machine too slow "
+                                    "or load too high")
 
         # virtual itimer should be (0.0, 0.0) now
         self.assertEquals(signal.getitimer(self.itimer), (0.0, 0.0))
@@ -455,9 +454,8 @@
             if signal.getitimer(self.itimer) == (0.0, 0.0):
                 break # sig_prof handler stopped this itimer
         else: # Issue 8424
-            sys.stdout.write("test_itimer_prof: timeout: likely cause: "
-                             "machine too slow or load too high.\n")
-            return
+            raise unittest.SkipTest("timeout: likely cause: machine too slow "
+                                    "or load too high")
 
         # profiling itimer should be (0.0, 0.0) now
         self.assertEquals(signal.getitimer(self.itimer), (0.0, 0.0))