Miscellaneous small improvements for scheduled_test.

pkg/scheduled_test/test/scheduled_server_test.dart

Index: pkg/scheduled_test/test/scheduled_server_test.dart
diff --git a/pkg/scheduled_test/test/scheduled_server_test.dart b/pkg/scheduled_test/test/scheduled_server_test.dart
index 5fc78120a3866f592ca33b2f4bb61d4d88370936..cc367730e1f3e23ec46928df118a5cfb95c9299e 100644
--- a/pkg/scheduled_test/test/scheduled_server_test.dart
+++ b/pkg/scheduled_test/test/scheduled_server_test.dart
@@ -35,10 +35,18 @@ void main() {
 
     test('test 2', () {
       expect(errors, everyElement(new isInstanceOf<ScheduleError>()));
-      expect(errors.length, equals(2));
+      // TODO(nweiz): There can be three errors due to issue 9151. The
+      // HttpParserException is reported without a stack trace, and so when it's
+      // wrapped twice it registers as a different exception each time (because
+      // it's given an ad-hoc stack trace). Always expect two exceptions when
+      // issue 9151 is fixed.
+      expect(errors.length, inInclusiveRange(2, 3));
       expect(errors[0].error, equals("'scheduled server 0' received GET /hello "
           "when no more requests were expected."));
       expect(errors[1].error, new isInstanceOf<HttpParserException>());
+      if (errors[2] != null) {
+        expect(errors[2].error, new isInstanceOf<HttpParserException>());
+      }
     });
   }, passing: ['test 2']);