Make the repeating argument to timers optional.

tests/standalone/src/TimerCancelTest.dart

Index: tests/standalone/src/TimerCancelTest.dart
diff --git a/tests/standalone/src/TimerCancelTest.dart b/tests/standalone/src/TimerCancelTest.dart
index 31ba336c6435cc90581c22e51b9f54064ac665f0..21b13c8494acdd08d8cd66306963b1c8f4ac0b25 100644
--- a/tests/standalone/src/TimerCancelTest.dart
+++ b/tests/standalone/src/TimerCancelTest.dart
@@ -20,10 +20,10 @@ class TimerCancelTest {
       Expect.equals(true, repeatTimer == 1);
     }
 
-     cancelTimer = new Timer(timeoutHandlerUnreachable, 1000, false);
+     cancelTimer = new Timer(timeoutHandlerUnreachable, 1000);
      cancelTimer.cancel();
-     new Timer(timeoutHandler, 1000, false);
-     cancelTimer = new Timer(timeoutHandlerUnreachable, 2000, false);
+     new Timer(timeoutHandler, 1000);
+     cancelTimer = new Timer(timeoutHandlerUnreachable, 2000);
      repeatTimer = 0;
      new Timer(timeoutHandlerRepeat, 1500, true);
   }