Remove internalized cons string types.

test/mjsunit/regress/regress-357103.js

Index: test/mjsunit/regress/regress-357103.js
diff --git a/test/mjsunit/test-hidden-string.js b/test/mjsunit/regress/regress-357103.js
similarity index 61%
copy from test/mjsunit/test-hidden-string.js
copy to test/mjsunit/regress/regress-357103.js
index a5d32c839ea38e08abedc2d95542009accdec36c..692729ddb34bd7932e238d74db972b7c81402896 100644
--- a/test/mjsunit/test-hidden-string.js
+++ b/test/mjsunit/regress/regress-357103.js
@@ -4,8 +4,11 @@
 
 // Flags: --allow-natives-syntax
 
+%SetFlags("--gc-interval=1");
+
+var key = "Huckleberry Finn" + "Tom Sawyer";
 var o = {};
-%SetHiddenProperty(o, "test", 1);
-// Create non-internalized ""
-var empty = "a".substring(1, 1);
-assertEquals(undefined, o[empty]);
+function f() { o[key] = "Adventures"; }
+
+f();
+f();