fix(autocomplete): two chips added on enter w/ IE11 (#11528)

Fixes #10640. Closes #10667.

Author: Splaktar

src/components/autocomplete/autocomplete.spec.js

@@ -54,6 +54,7 @@ describe('<md-autocomplete>', function() {
   function keydownEvent(keyCode) {
     return {
       keyCode: keyCode,
+      stopImmediatePropagation: angular.noop,
       stopPropagation: angular.noop,
       preventDefault: angular.noop
     };

src/components/autocomplete/js/autocompleteController.js

@@ -583,7 +583,7 @@ function MdAutocompleteCtrl ($scope, $element, $mdUtil, $mdConstant, $mdTheming,
       case $mdConstant.KEY_CODE.ENTER:
         if (ctrl.hidden || ctrl.loading || ctrl.index < 0 || ctrl.matches.length < 1) return;
         if (hasSelection()) return;
-        event.stopPropagation();
+        event.stopImmediatePropagation();
         event.preventDefault();
         select(ctrl.index);
         break;