[generators] Always call function with closure context when resuming.

test/mjsunit/regress/regress-681171-1.js

Index: test/mjsunit/regress/regress-681171-1.js
diff --git a/test/mjsunit/regress/regress-681171-1.js b/test/mjsunit/regress/regress-681171-1.js
new file mode 100644
index 0000000000000000000000000000000000000000..41c91e81f9bb2a49f0de9a3cffdc122e1bdbcaf1
--- /dev/null
+++ b/test/mjsunit/regress/regress-681171-1.js
@@ -0,0 +1,13 @@
+// Copyright 2017 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Flags: --always-opt --function-context-specialization --verify-heap
+
+bar = function() { }
+
+try {
+  (function() {
+     bar(...(function*(){ yield 1; yield 2; yield 3; })());
+   })();
+} catch(e) {}