[tests] Cleanup tests that use assertOptimized()/assertUnoptimized().

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 --allow-natives-syntax
+// Flags: --harmony-do-expressions --allow-natives-syntax --no-always-opt
+// Flags: --crankshaft
 
 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 280 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();