Use a different map to distinguish eval contexts

test/mjsunit/regress/regress-5295.js

Index: test/mjsunit/regress/regress-5295.js
diff --git a/test/mjsunit/regress/regress-5295.js b/test/mjsunit/regress/regress-5295.js
new file mode 100644
index 0000000000000000000000000000000000000000..e635748e78c2d650f0ee26c1581aa4410c1b49f1
--- /dev/null
+++ b/test/mjsunit/regress/regress-5295.js
@@ -0,0 +1,12 @@
+// 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.
+
+eval('var x; let y; ()=>y');
+assertEquals(undefined, x);
+
+function foo() {
+  eval('var z = 1; let w; ()=>w');
+  return z;
+}
+assertEquals(1, foo());