Use a different map to distinguish eval contexts

test/mjsunit/regress/regress-648719.js

Index: test/mjsunit/regress/regress-648719.js
diff --git a/test/mjsunit/regress/regress-648719.js b/test/mjsunit/regress/regress-648719.js
new file mode 100644
index 0000000000000000000000000000000000000000..c2df607b8d23981b7c623e861041b26b306947ed
--- /dev/null
+++ b/test/mjsunit/regress/regress-648719.js
@@ -0,0 +1,5 @@
+// Copyright 2016 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.
+
+assertEquals('function', typeof eval('const xz = {};function yz(){xz}yz'));