pkg/unittest: Capture stackTrace in all failure cases

pkg/unittest/lib/src/test_case.dart

Index: pkg/unittest/lib/src/test_case.dart
diff --git a/pkg/unittest/lib/src/test_case.dart b/pkg/unittest/lib/src/test_case.dart
index e1d38750e3bbf15b1227df1e0b825eb0bcfb9342..dc2f59289b152b21d2ba43707df9c8dc5f622a16 100644
--- a/pkg/unittest/lib/src/test_case.dart
+++ b/pkg/unittest/lib/src/test_case.dart
@@ -70,15 +70,7 @@ class TestCase {
 
   bool get isComplete => !enabled || result != null;
 
-  Function _errorHandler(String stage) => (e) {
-    var stack;
-    // TODO(kevmoo): Ideally, getAttachedStackTrace should handle Error as well?
-    // https://code.google.com/p/dart/issues/detail?id=12240
-    if(e is Error) {
-      stack = e.stackTrace;
-    } else {
-      stack = getAttachedStackTrace(e);
-    }
+  Function _errorHandler(String stage) => (Object e, StackTrace stack) {
     if (result == null || result == PASS) {
       if (e is TestFailure) {
         fail("$e", stack);