Remove --promise-extra flag

test/mjsunit/es6/debug-promises/reject-with-undefined-reject.js

Index: test/mjsunit/es6/debug-promises/reject-with-undefined-reject.js
diff --git a/test/mjsunit/es6/debug-promises/reject-with-undefined-reject.js b/test/mjsunit/es6/debug-promises/reject-with-undefined-reject.js
index d058d41b96e489bcba346d6e8cd31519fb43f3ce..1595372396a97ffbe10d1106e6fd6c8ca4d80328 100644
--- a/test/mjsunit/es6/debug-promises/reject-with-undefined-reject.js
+++ b/test/mjsunit/es6/debug-promises/reject-with-undefined-reject.js
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// Flags: --expose-debug-as debug --allow-natives-syntax --promise-extra
+// Flags: --expose-debug-as debug --allow-natives-syntax
 
 // Test debug events when a Promise is rejected, which is caught by a custom
 // promise, which has undefined for reject closure.  We expect an Exception
@@ -28,7 +28,7 @@ function MyPromise(resolver) {
 MyPromise.prototype = new Promise(function() {});
 p.constructor = MyPromise;
 
-var q = p.chain(
+var q = p.then(
   function() {
     log.push("reject caught");
     return Promise.reject(new Error("caught"));