[arm64] Don't try convert binary operation to shifted form when both operands are the same.

test/mjsunit/regress/regress-crbug-523307.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: --allow-natives-syntax
 
-function f() { return f.x; }
-f.__proto__ = null;
-f.prototype = "";
+function f(x) {
+  var c = x * x << 366;
+  var a = c + c;
+  return a;
+}
 
-f();
-f();
+f(1);
+f(1);
 %OptimizeFunctionOnNextCall(f);
-f();
+f(1);