Add an example of using assert.throws

Author: domenic

test/suite/es6/ch25/25.4/25.4.3/25.4.3.1/S25.4.3.1_A2.2_T1.js

@@ -6,9 +6,10 @@ info: >
     Promise throws TypeError when 'this' is constructed but unsettled promise
 author: Sam Mikes
 description: Promise.call(new Promise()) throws TypeError
-negative: TypeError
 ---*/
 
 var p = new Promise(function() {});
 
-Promise.call(p, function () {});
+assert.throws(function () {
+    Promise.call(p, function () {});
+});