Speed up two unit tests to avoid timeouts and make tests finish faster.

test/mjsunit/string-replace-one-char.js

 // Copyright 2012 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 53 matching lines @@
 test_replace(not_found_1, not_found_1, "+", "-");
 
 var not_found_2 = prefix1024 + "abcdefghijklm\u1234nopqrstuvwxyz";
 test_replace(not_found_2, not_found_2, "+", "---");
 
 var not_found_3 = prefix1024 + "abcdefghijklmnopqrstuvwxyz";
 test_replace(not_found_3, not_found_3, "\u1234", "ZZZ");
 
 // Deep cons tree.
 var nested_1 = "";
-for (var i = 0; i < 1000000; i++) nested_1 += "y";
+for (var i = 0; i < 100000; i++) nested_1 += "y";
 var nested_1_result = prefix1024 + nested_1 + "aa";
 nested_1 = prefix1024 + nested_1 + "z";
 test_replace(nested_1, nested_1_result, "z", "aa");
 
 var nested_2 = "\u2244";
-for (var i = 0; i < 1000000; i++) nested_2 += "y";
+for (var i = 0; i < 100000; i++) nested_2 += "y";
 var nested_2_result = prefix1024 + nested_2 + "aa";
 nested_2 = prefix1024 + nested_2 + "\u2012";
 test_replace(nested_2, nested_2_result, "\u2012", "aa");
 
 // Sliced string as input.  A cons string is always flattened before sliced.
 var slice_1 = ("ab" + prefix1024 + "cdefghijklmnopqrstuvwxyz").slice(1, -1);
 var slice_1_result = "b" + prefix1024 + "cdefghijklmnopqrstuvwxQ";
 test_replace(slice_1, slice_1_result, "y", "Q");
 
 var slice_2 = (prefix1024 + "abcdefghijklmno\u1234\u1234p").slice(1, -1);
 var slice_2_result = prefix1024.substr(1) + "abcdefghijklmnoQ\u1234";
 test_replace(slice_2, slice_2_result, "\u1234", "Q");