Increase coverage testing of sparse arrays. Add a set...

test/mjsunit/array-splice-webkit.js

 // Copyright 2008 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 39 matching lines @@
 assertArrayEquals(['a','b','c'], arr);
 
 assertArrayEquals([], arr.splice(2, undefined))
 assertArrayEquals([], arr.splice(2, null))
 assertArrayEquals([], arr.splice(2, -1))
 assertArrayEquals([], arr.splice(2, 0))
 assertArrayEquals(['a','b','c'], arr);
 assertArrayEquals(['c'], arr.splice(2, 100))
 assertArrayEquals(['a','b'], arr);
 
+// Verify preservation of the hole while shifting
+arr = ['a','b','c','d','e'];
+assertTrue(3 in arr);
+assertTrue(delete arr[3]);
+assertFalse(3 in arr);
+res = arr.splice(2,2);
+assertArrayEquals(['a','b','e'], arr);
+assertArrayEquals(['c',,], res);
+assertFalse(1 in res);