[crankshaft] Fixing ES6 tail call elimination.

test/mjsunit/es6/tail-call-simple.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 --harmony-tailcalls --stack-size=100
-// TODO(v8:4698), TODO(ishell): support these cases.
-// Flags: --nostress-opt
 
 //
 // Tail calls work only in strict mode.
 //
 (function() {
   function f(n) {
     if (n <= 0) {
       return "foo";
     }
     return f(n - 1);
@@ skipping 118 matching lines @@
   var g_bound = g0.bind({});
   function f(n) {
     return f_bound(n);
   }
   assertEquals("foo", f(1e5));
   assertEquals("bar", f(1e5 + 1));
   %OptimizeFunctionOnNextCall(f);
   assertEquals("foo", f(1e5));
   assertEquals("bar", f(1e5 + 1));
 })();