[angular_test] running in browser results in "Bad state" exception

[chalin]

This is using Angular 4.0.0 and angular_test 1.0.0. To reproduce:

• Setup the AngularDart doc starter project.
• pub get
• Launch Dartium.
• pub serve
• Open http://localhost:8081/app_test.html

All tests pass. The following is displayed on the console:

00:00 : All tests passed!

But, this exception is thrown:

VM161:1 EXCEPTION: Bad state: Cannot fire new event. Controller is already firing an event
STACKTRACE: 
#0      _BroadcastStreamController.add (dart:async/broadcast_stream_controller.dart:253)
#1      NgZone._checkStable.<anonymous closure> (package:angular/src/core/zone/ng_zone.dart:274:53)
#2      _rootRun (dart:async/zone.dart:1116)
#3      _CustomZone.run (dart:async/zone.dart:1001)
#4      NgZone.runOutsideAngular (package:angular/src/core/zone/ng_zone.dart:326:23)
#5      NgZone._checkStable (package:angular/src/core/zone/ng_zone.dart:273:15)
#6      NgZone._onLeave (package:angular/src/core/zone/ng_zone.dart:213:5)
#7      NgZone._runUnary (package:angular/src/core/zone/ng_zone.dart:186:7)
#8      _CustomZone.runUnary (dart:async/zone.dart:1012)
#9      _CustomZone.runUnaryGuarded (dart:async/zone.dart:909)
#10     _BufferingStreamSubscription._sendData (dart:async/stream_impl.dart:330)
#11     _BufferingStreamSubscription._add (dart:async/stream_impl.dart:257)
#12     _SyncBroadcastStreamController._sendData.<anonymous closure> (dart:async/broadcast_stream_controller.dart:387)
#13     _BroadcastStreamController._forEachListener (dart:async/broadcast_stream_controller.dart:328)
#14     _SyncBroadcastStreamController._sendData (dart:async/broadcast_stream_controller.dart:386)
#15     _BroadcastStreamController.add (dart:async/broadcast_stream_controller.dart:254)
#16     NgZone._checkStable.<anonymous closure> (package:angular/src/core/zone/ng_zone.dart:274:53)
#17     _rootRun (dart:async/zone.dart:1120)
#18     _CustomZone.run (dart:async/zone.dart:1001)
#19     NgZone.runOutsideAngular (package:angular/src/core/zone/ng_zone.dart:326:23)
#20     NgZone._checkStable (package:angular/src/core/zone/ng_zone.dart:273:15)
#21     NgZone._onLeave (package:angular/src/core/zone/ng_zone.dart:213:5)
#22     NgZone._run (package:angular/src/core/zone/ng_zone.dart:177:7)
#23     _CustomZone.run (dart:async/zone.dart:1001)
#24     _CustomZone.runGuarded (dart:async/zone.dart:901)
#25     _CustomZone.bindCallback.<anonymous closure> (dart:async/zone.dart:926)
#26     _microtaskLoop (dart:async/schedule_microtask.dart:41)
#27     _startMicrotaskLoop (dart:async/schedule_microtask.dart:50)
#28     _ScheduleImmediateHelper._handleMutation (dart:html:53852)

ORIGINAL EXCEPTION: Bad state: Cannot fire new event. Controller is already firing an event

cc @kwalrath