Add test ensuring withEnvironment flag is honored

test/language/global-code/unscopables-ignored.js

+// Copyright (c) 2016 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-global-environment-records-hasbinding-n
+es6id: 8.1.1.4.1
+description: >
+  Symbol.unscopables is not referenced for the object environment of the global
+  environment record
+info: |
+  1. Let envRec be the global Environment Record for which the method was invoked.
+  2. Let DclRec be envRec.[[DeclarativeRecord]].
+  3. If DclRec.HasBinding(N) is true, return true.
+  4. Let ObjRec be envRec.[[ObjectRecord]].
+  5. Return ? ObjRec.HasBinding(N).
+
+  8.1.1.2.1 HasBinding
+
+  1. Let envRec be the object Environment Record for which the method was
+     invoked.
+  2. Let bindings be the binding object for envRec.
+  3. Let foundBinding be ? HasProperty(bindings, N).
+  4. If foundBinding is false, return false.
+  5. If the withEnvironment flag of envRec is false, return true.
+  6. Let unscopables be ? Get(bindings, @@unscopables).
+  7. If Type(unscopables) is Object, then
+     a. Let blocked be ToBoolean(? Get(unscopables, N)).
+     b. If blocked is true, return false.
+  8. Return true.
+features: [Symbol.unscopables]
+---*/
+
+var callCount = 0;
+Object.defineProperty(this, Symbol.unscopables, {
+  get: function() {
+    callCount += 1;
+  }
+});
+
+this.test262 = true;
+
+test262;
+
+assert.sameValue(
+  callCount, 0, 'Did not reference @@unscopables property of global object'
+);