Merged: [crankshaft] Disable further folding already folded allocations.

test/mjsunit/regress/regress-crbug-621868.js

 // Copyright 2016 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: --allow-natives-syntax --turbo
+// Flags: --allow-natives-syntax --verify-heap
 
-function f() {
-  var o = {};
-  o.a = 1;
+function f(a) {  // First parameter is tagged.
+  var n = 1 + a;
 }
+
 function g() {
-  var o = { ['a']: function(){} };
   f();
+  var d = {x : f()};
+  return [d];
 }
-f();
-f();
+
+g();
+g();
 %OptimizeFunctionOnNextCall(g);
 g();