Attempt to fix timeout of failing selenium tests.

dart/pkg/unittest/test_controller.js

Index: dart/pkg/unittest/test_controller.js
diff --git a/dart/pkg/unittest/test_controller.js b/dart/pkg/unittest/test_controller.js
index 5b2152103bf5aff2ecc26f92523f547632898e50..b247f6e7df037ff8920aa973254d58f3a8350675 100644
--- a/dart/pkg/unittest/test_controller.js
+++ b/dart/pkg/unittest/test_controller.js
@@ -109,6 +109,10 @@ function dartPrint(msg) {
 // Dart [main] directly. The argument is a closure that invokes main.
 function dartMainRunner(main) {
   window.postMessage('dart-calling-main', '*');
-  main();
+  try {
+    main();
+  } catch (e) {
+    showErrorAndExit(String(e));
+  }
   window.postMessage('dart-main-done', '*');
 }