Update the isArray operation to handle proxy objects (#3666)

Added step 3. from ECMA-262 v6, 7.2.2

JerryScript-DCO-1.0-Signed-off-by: Adam Szilagyi aszilagy@inf.u-szeged.hu

tests/jerry/es2015/array-isarray.js

@@ -0,0 +1,48 @@
+// Copyright JS Foundation and other contributors, http://js.foundation
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+assert(Array.isArray([]) === true);
+assert(Array.isArray([1]) === true);
+assert(Array.isArray(new Array()) === true);
+assert(Array.isArray(new Array('a', 'b', 'c', 'd')) === true);
+assert(Array.isArray(new Array(3)) === true);
+assert(Array.isArray(Array.prototype) === true);
+assert(Array.isArray(new Proxy([], {})) === true);
+
+assert(Array.isArray() === false);
+assert(Array.isArray({}) === false);
+assert(Array.isArray(null) === false);
+assert(Array.isArray(undefined) === false);
+assert(Array.isArray(17) === false);
+assert(Array.isArray('Array') === false);
+assert(Array.isArray(true) === false);
+assert(Array.isArray(false) === false);
+assert(Array.isArray(new Uint8Array(32)) === false);
+assert(Array.isArray({ __proto__: Array.prototype }) === false);
+
+var revocable = Proxy.revocable ({}, {});
+var proxy = revocable.proxy;
+revocable.revoke();
+
+try {
+  Array.isArray(proxy);
+  assert(false);
+} catch (e) {
+  assert(e instanceof TypeError);
+}
+
+var revocable = Proxy.revocable ([], {});
+var proxy = revocable.proxy;
+
+assert(Array.isArray(proxy) === true);