Unit test improvements:

pkg/unittest/lib/unittest.dart

Index: pkg/unittest/lib/unittest.dart
===================================================================
--- pkg/unittest/lib/unittest.dart	(revision 18360)
+++ pkg/unittest/lib/unittest.dart	(working copy)
@@ -354,6 +354,18 @@
       _testCase.callbackFunctionsOutstanding++;
     }
     _id = '';
+    // If the callback is not an anonymous closure, try to get the
+    // name.
+    var fname = callback.toString();
+    var prefix = "Function '";
+    var pos = fname.indexOf(prefix);
+    if (pos > 0) {
+      pos += prefix.length;
+      var epos = fname.indexOf("'", pos);
+      if (epos > 0) {
+        _id = "${fname.substring(pos, epos)} ";
+      }
+    }
   }
 
   _SpreadArgsHelper(callback, shouldCallBack, isDone) {