fix(jqLite): triggerHandler support unbind self

Fixes .one if the event is invoked from triggerHandler.

Closes #5984

Author: chrisirhc

src/jqLite.js

@@ -948,7 +948,9 @@ forEach({
   clone: jqLiteClone,
 
   triggerHandler: function(element, eventName, eventData) {
-    var eventFns = (jqLiteExpandoStore(element, 'events') || {})[eventName];
+    // Copy event handlers in case event handlers array is modified during execution.
+    var eventFns = (jqLiteExpandoStore(element, 'events') || {})[eventName],
+        eventFnsCopy = shallowCopy(eventFns || []);
 
     eventData = eventData || [];
 
@@ -962,7 +964,7 @@ forEach({
       stopPropagation: noop
     }];
 
-    forEach(eventFns, function(fn) {
+    forEach(eventFnsCopy, function(fn) {
       fn.apply(element, event.concat(eventData));
     });
   }

test/jqLiteSpec.js

@@ -1743,6 +1743,26 @@ describe('jqLite', function() {
       event.preventDefault();
       expect(event.isDefaultPrevented()).toBe(true);
     });
+
+
+    it('should support handlers that deregister themselves', function() {
+      var element = jqLite('<a>poke</a>'),
+          clickSpy = jasmine.createSpy('click'),
+          clickOnceSpy = jasmine.createSpy('clickOnce').andCallFake(function() {
+            element.off('click', clickOnceSpy);
+          });
+
+      element.on('click', clickOnceSpy);
+      element.on('click', clickSpy);
+
+      element.triggerHandler('click');
+      expect(clickOnceSpy).toHaveBeenCalledOnce();
+      expect(clickSpy).toHaveBeenCalledOnce();
+
+      element.triggerHandler('click');
+      expect(clickOnceSpy).toHaveBeenCalledOnce();
+      expect(clickSpy.callCount).toBe(2);
+    });
   });