Revert "[vm] Prevent non-fatal errors from causing timers to be dropped."

runtime/lib/timer_impl.dart

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 import 'dart:_internal' hide Symbol;
 
 // Timer heap implemented as a array-based binary heap[0].
 // This allows for O(1) `first`, O(log(n)) `remove`/`removeFirst` and O(log(n))
 // `add`.
 //
@@ skipping 330 matching lines @@
 
     // Fast exit if no pending timers.
     if (pendingTimers.length == 0) {
       return;
     }
 
     // Trigger all of the pending timers. New timers added as part of the
     // callbacks will be enqueued now and notified in the next spin at the
     // earliest.
     _handlingCallbacks = true;
-    var i = 0;
     try {
-      for (; i < pendingTimers.length; i++) {
+      for (var i = 0; i < pendingTimers.length; i++) {
         // Next pending timer.
         var timer = pendingTimers[i];
         timer._indexOrNext = null;
 
         // One of the timers in the pending_timers list can cancel
         // one of the later timers which will set the callback to
         // null. Or the pending zero timer has been canceled earlier.
         if (timer._callback != null) {
           var callback = timer._callback;
           if (!timer._repeating) {
             // Mark timer as inactive.
             timer._callback = null;
           }
           callback(timer);
           // Re-insert repeating timer if not canceled.
           if (timer._repeating && (timer._callback != null)) {
             timer._advanceWakeupTime();
             timer._enqueue();
           }
           // Execute pending micro tasks.
           var immediateCallback = _removePendingImmediateCallback();
           if (immediateCallback != null) {
             immediateCallback();
           }
         }
       }
     } finally {
       _handlingCallbacks = false;
-      // Re-queue timers we didn't get to.
-      for (i++; i < pendingTimers.length; i++) {
-        var timer = pendingTimers[i];
-        timer._enqueue();
-      }
-      _notifyEventHandler();
     }
   }
 
   static void _handleMessage(msg) {
     var pendingTimers;
     if (msg == _ZERO_EVENT) {
       pendingTimers = _queueFromZeroEvent();
       assert(pendingTimers.length > 0);
     } else {
       assert(msg == _TIMEOUT_EVENT);
@@ skipping 45 matching lines @@
     if (repeating) {
       return new _Timer.periodic(milliSeconds, callback);
     }
     return new _Timer(milliSeconds, callback);
   }
 }
 
 _setupHooks() {
   VMLibraryHooks.timerFactory = _Timer._factory;
 }