Internalize strings being stored into uninitialized property cells

test/mjsunit/string-slices.js

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 175 matching lines @@
 assertEquals("\u03B1\u03B4\u03B5", utf.substring(0,1) + utf.substring(5,3));
 assertEquals("", ascii.substring(16) + utf.substring(16));
 assertEquals("bcdef\u03B4\u03B5\u03B6\u03B7\u03B8\u03B9",
     ascii.substring(1,6) + utf.substring(3,9));
 assertEquals("\u03B4\u03B5\u03B6\u03B7\u03B8\u03B9abcdefghijklmnop",
     utf.substring(3,9) + ascii);
 assertEquals("\u03B2\u03B3\u03B4\u03B5\u03B4\u03B5\u03B6\u03B7",
     utf.substring(5,1) + utf.substring(3,7));
 
 // Externalizing strings.
-var a = "123456789" + "qwertyuiopasdfghjklzxcvbnm";
+var a = "internalized dummy";
+a = "123456789" + "qwertyuiopasdfghjklzxcvbnm";
 var b = "23456789qwertyuiopasdfghjklzxcvbn"
 assertEquals(a.slice(1,-1), b);
 
 assertTrue(isOneByteString(a));
 externalizeString(a, true);
 assertFalse(isOneByteString(a));
 
 assertEquals(a.slice(1,-1), b);
 assertTrue(/3456789qwe/.test(a));
 assertEquals(5, a.indexOf("678"));
@@ skipping 20 matching lines @@
 var s1 = "12345678901234567890";
 var s2 = "abcdefghijklmnopqrstuvwxyz";
 var c1 = s1 + s2;
 var c2 = s1 + c1 + s2;
 assertEquals("234567890123456789", c1.substring(1, 19));
 assertEquals("bcdefghijklmno", c1.substring(21, 35));
 assertEquals("2345678901234567890abcdefghijklmno", c1.substring(1, 35));
 assertEquals("234567890123456789", c2.substring(1, 19));
 assertEquals("bcdefghijklmno", c2.substring(41, 55));
 assertEquals("2345678901234567890abcdefghijklmno", c2.substring(21, 55));