Add coalesce expression test

test/annexB/language/expressions/coalesce/emulates-undefined.js

@@ -0,0 +1,20 @@
+// Copyright (C) 2020 Alexey Shvayka. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-binary-bitwise-operators-runtime-semantics-evaluation
+description: >
+  ?? doesn't special-case [[IsHTMLDDA]] object; rval is not evaluated.
+info: |
+  CoalesceExpression : CoalesceExpressionHead ?? BitwiseORExpression
+
+  1. Let lref be the result of evaluating CoalesceExpressionHead.
+  2. Let lval be ? GetValue(lref).
+  3. If lval is undefined or null, then
+    [...]
+  4. Otherwise, return lval.
+features: [IsHTMLDDA, coalesce-expression]
+---*/
+
+var IsHTMLDDA = $262.IsHTMLDDA;
+
+assert.sameValue(IsHTMLDDA ?? unresolved, IsHTMLDDA);