fix(patch): fix #618, use zoneSymbol as property name to avoid name conflict

Author: JiaLiPassion

lib/common/utils.ts

@@ -74,7 +74,7 @@ export function patchProperty(obj, prop) {
 
   // substr(2) cuz 'onclick' -> 'click', etc
   const eventName = prop.substr(2);
-  const _prop = '_' + prop;
+  const _prop = zoneSymbol('_' + prop);
 
   desc.set = function(fn) {
     if (this[_prop]) {

test/common/microtasks.spec.ts

@@ -106,4 +106,3 @@ describe('Microtasks', function() {
     });
   });
 });
-export let __something__;

test/common/util.spec.ts

@@ -80,4 +80,3 @@ describe('utils', function() {
   });
 
 });
-export let __something__;