Eagerly close browser tests.

test/runner/signal_test.dart

Index: test/runner/signal_test.dart
diff --git a/test/runner/signal_test.dart b/test/runner/signal_test.dart
index 63e8e7bd22d7e5dea8e489607de5e99548e92ea0..1211b709c6e7066750b6170ef1e8e6d8172722f7 100644
--- a/test/runner/signal_test.dart
+++ b/test/runner/signal_test.dart
@@ -252,8 +252,10 @@ void main() {
   });
 }
 
-ScheduledProcess _runTest(List<String> args) =>
-    runTest(args, environment: {"_UNITTEST_TEMP_DIR": _tempDir});
+ScheduledProcess _runTest(List<String> args, {bool forwardStdio: false}) =>
+    runTest(args,
+        environment: {"_UNITTEST_TEMP_DIR": _tempDir},
+        forwardStdio: forwardStdio);
 
 void signalAndQuit(ScheduledProcess test) {
   test.signal(ProcessSignal.SIGTERM);