Add Object.is test

test/annexB/built-ins/Object/is/emulates-undefined.js

@@ -0,0 +1,26 @@
+// Copyright (C) 2020 Alexey Shvayka. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-object.is
+description: >
+  SameValue abstract op doesn't special-case [[IsHTMLDDA]] objects.
+info: |
+  Object.is ( value1, value2 )
+
+  1. Return SameValue(value1, value2).
+
+  SameValue ( x, y )
+
+  1. If Type(x) is different from Type(y), return false.
+features: [IsHTMLDDA]
+---*/
+
+var IsHTMLDDA = $262.IsHTMLDDA;
+
+assert.sameValue(Object.is(IsHTMLDDA, undefined), false, "SameValue with `undefined`");
+assert.sameValue(Object.is(undefined, IsHTMLDDA), false, "SameValue with `undefined`");
+
+assert.sameValue(Object.is(IsHTMLDDA, null), false, "SameValue with `null`");
+assert.sameValue(Object.is(null, IsHTMLDDA), false, "SameValue with `null`");
+
+assert(Object.is(IsHTMLDDA, IsHTMLDDA));