Move delete-last-fast-property code from CSA to C++

test/mjsunit/regress/regress-crbug-716912.js

+// Copyright 2017 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: --expose-gc --invoke-weak-callbacks
+
+function __f_6() {
+this.a4 = {};
+}
+__v_6 = new __f_6();
+__v_6.prototype = __v_6;
+__v_6 = new __f_6();
+gc();
+gc();
+
+buf = new ArrayBuffer(8);
+__v_8 = new Int32Array(buf);
+__v_9 = new Float64Array(buf);
+
+__v_8[0] = 1;
+__v_6.a4 = {a: 0};
+delete __v_6.a4;
+__v_6.boom = __v_9[0];