make tests return nonzero if failing

http://codereview.appspot.com/4545042/



git-svn-id: http://skia.googlecode.com/svn/trunk@1323 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/tests/skia_test.cpp b/tests/skia_test.cpp
index 25248a3..f931d62 100644
--- a/tests/skia_test.cpp
+++ b/tests/skia_test.cpp
@@ -123,5 +123,5 @@
         SkDebugf("Finished %d tests, %d failures.\n", count,
                  count - successCount);
     }
-    return 0;
+    return (count == successCount) ? 0 : 1;
 }