Implement Object.is routine from ES2015 specification (#3272)

Related part of the standard: ECMA-262 v6, 19.1.2.10

JerryScript-DCO-1.0-Signed-off-by: Adam Kallai kadam@inf.u-szeged.hu

tests/jerry/es2015/object-is.js

@@ -0,0 +1,56 @@
+// 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(Object.is(2, "foo") === false);
+assert(Object.is(null, 2) === false);
+
+var x;
+assert(Object.is(x, 2) === false);
+
+assert(Object.is(null, null) === true);
+
+assert(Object.is(2, 8) === false);
+assert(Object.is(8, 8) === true);
+
+assert(Object.is('foo', 'foo') === true);
+assert(Object.is('foo', 'bar') === false);
+assert(Object.is(new String('foo'), 'foo') === false);
+
+assert(Object.is([], []) === false);
+
+assert(Object.is(true, true) === true);
+assert(Object.is(false, false) === true);
+assert(Object.is(true, false) === false);
+assert(Object.is(false, true) === false);
+assert(Object.is("", false) === false);
+assert(Object.is(0, false) === false);
+
+sym1 = Symbol.for('foo');
+sym2 = Symbol.for('foo');
+assert(Object.is(sym1, sym2) === true);
+assert(Object.is(Symbol('foo'), Symbol('foo')) === false);
+
+var foo = { a: 1 };
+var bar = { a: 1 };
+var zoo = foo;
+assert(Object.is(foo, foo) === true);
+assert(Object.is(foo, bar) === false);
+assert(Object.is(foo, zoo) === true);
+
+// Special Cases
+assert(Object.is(+0, -0) === false);
+assert(Object.is(+0, 0) === true);
+assert(Object.is(-0, -0) === true);
+assert(Object.is(-0, 0) === false);
+assert(Object.is(NaN, 0/0) === true);