Adapt tests in preparation of shipping --harmony-completion.

test/mjsunit/harmony/do-expressions.js

 // Copyright 2015 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // Flags: --harmony-do-expressions --harmony-sloppy-let --allow-natives-syntax
 // Flags: --harmony-default-parameters --harmony-destructuring
+// Flags: --harmony-completion
 
 function returnValue(v) { return v; }
 function MyError() {}
 var global = this;
 
 function TestBasic() {
   // Looping and lexical declarations
   assertEquals(512, returnValue(do {
     let n = 2;
     for (let i = 0; i < 4; i++) n <<= 2;
@@ skipping 143 matching lines @@
   var last_name = "Jetson";
   function fn1(name = do { first_name + " " + last_name }) {
     return name;
   }
   assertEquals("George Jetson", fn1());
 
   var _items = [1, 2, 3, NaN, 4, 5];
   function fn2(items = do {
     let items = [];
     for (var el of _items) {
-      if (el !== el) break;
+      if (el !== el) {
+        items;
+        break;
+      }
       items.push(el), items;
     }
   }) {
     return items;
   }
   assertEquals([1, 2, 3], fn2());
 
   function thrower() { throw new MyError(); }
   function fn3(exception = do {  try { thrower(); } catch (e) { e } }) {
     return exception;
@@ skipping 83 matching lines @@
     let nums = [];
     for (let i = 0; i < 1000; ++i) {
       let value = (Math.random() * 100) | 0;
       nums.push(value === 0 ? 1 : value), nums;
     }
   };
   assertEquals(numbers.length, 1000);
 }
 
 for (var i = 0; i < 64; ++i) TestOSR();