Fix service test websocket error edge case

runtime/observatory/tests/service/test_helper.dart

Index: runtime/observatory/tests/service/test_helper.dart
diff --git a/runtime/observatory/tests/service/test_helper.dart b/runtime/observatory/tests/service/test_helper.dart
index 6897588099212ec5b54fa3c9bc842c06f08ad947..858a23314eed7fd4fe62ffca200dd2792dfac1af 100644
--- a/runtime/observatory/tests/service/test_helper.dart
+++ b/runtime/observatory/tests/service/test_helper.dart
@@ -16,11 +16,6 @@ import 'service_test_common.dart';
 String serviceHttpAddress;
 String serviceWebsocketAddress;
 
-bool _isWebSocketDisconnect(e) {
-  return e is NetworkRpcException;
-}
-
-
 const String _TESTEE_ENV_KEY = 'SERVICE_TEST_TESTEE';
 const Map<String, String> _TESTEE_SPAWN_ENV = const {
   _TESTEE_ENV_KEY: 'true'
@@ -303,11 +298,8 @@ class _FlutterDeviceServiceTesterRunner {
           await test(isolate);
         }
       }
-    }, onError: (e, st) {
-        if (!_isWebSocketDisconnect(e)) {
-          print('Unexpected exception in service tests: $e $st');
-          throw e;
-        }
+    }, onError: (error, stackTrace) {
+      print('Unexpected exception in service tests: $error\n$stackTrace');
     });
   }
 }
@@ -372,19 +364,10 @@ class _ServiceTesterRunner {
         }
 
         await process.requestExit();
-      }, onError: (e, st) {
+      }, onError: (error, stackTrace) {
         process.requestExit();
-        // TODO: remove this workaround.
-        // This is necessary due to non awaited operations.
-        // E.G. object.dart (398~402)
-        // When an exception is thrown inside a test (directly or via await) the
-        // stacktrace is non-null and shows where the exception has been thrown.
-        // If vice versa the exception is due to an error in a non-awaited
-        // Future the stacktrace is null.
-        if (st != null || !_isWebSocketDisconnect(e)) {
-          print('Unexpected exception in service tests: $e $st');
-          throw e;
-        }
+        print('Unexpected exception in service tests: $error\n$stackTrace');
+        throw error;
       });
     });
   }