Remove empty comma expressions

tests/baselines/reference/computedPropertyNames11_ES5.js

@@ -46,8 +46,6 @@ var v = (_a = {},
         enumerable: true,
         configurable: true
     }),
-    ,
-    ,
     Object.defineProperty(_a, a, {
         set: function (v) { },
         enumerable: true,

tests/baselines/reference/computedPropertyNames49_ES5.js

@@ -60,7 +60,6 @@ var x = (_a = {
         enumerable: true,
         configurable: true
     }),
-    ,
     _a.p2 = 20,
     _a);
 var _a;