Fix ToObject and Object.isSealed in four Array builtins.

test/mjsunit/regress/regress-builtinbust-6.js

+// Copyright 2014 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.
+
+// Test that Array builtins can be called on primitive values.
+var values = [ 23, 4.2, true, false, 0/0 ];
+for (var i = 0; i < values.length; ++i) {
+  var v = values[i];
+  Array.prototype.pop.call(v);
+  Array.prototype.push.call(v);
+  Array.prototype.shift.call(v);
+  Array.prototype.unshift.call(v);
+}
+
+// Test that ToObject on primitive values is only called once.
+var length_receiver, element_receiver;
+function length() { length_receiver = this; return 1; }
+function element() { element_receiver = this; return "x"; }
+Object.defineProperty(Number.prototype, "length", { get:length, set:length });
+Object.defineProperty(Number.prototype, "0", { get:element, set:element });
+Object.defineProperty(Number.prototype, "1", { get:element, set:element });
+
+assertDoesNotThrow("Array.prototype.pop.call(23)");
+assertEquals(new Number(23), length_receiver);
+assertSame(length_receiver, element_receiver);
+
+assertDoesNotThrow("Array.prototype.push.call(42, 'y')");
+assertEquals(new Number(42), length_receiver);
+assertSame(length_receiver, element_receiver);
+
+assertDoesNotThrow("Array.prototype.shift.call(65)");
+assertEquals(new Number(65), length_receiver);
+assertSame(length_receiver, element_receiver);
+
+assertDoesNotThrow("Array.prototype.unshift.call(99, 'z')");
+assertEquals(new Number(99), length_receiver);
+assertSame(length_receiver, element_receiver);