Write a regression test for JDK-4525475

Issue:
JFileChooser allows modification to the file-system by way of the "New Folder"
button, and the ability to rename file/folder names. There is no method on
JFileChooser which indicates that this type of modification should not be
allowed within the given JFileChooser.

Testing:
1. Tested using Mach5(20 times per platform) in macos,linux and windows and got all pass.
2. Tested in original failed Java version and the fixed version;
Java 1.4.0 -> Test Failed.
$ j2sdk1.4.0/bin/java Bug4525475
LookAndFeel: com.sun.java.swing.plaf.windows.WindowsLookAndFeel
Name = Go Up, readOnly = true
Name = New Folder, readOnly = true
Its a Read Only JFileChooser and has a New Folder Button. So Test Failed.
Name = Go Up, readOnly = false
Name = New Folder, readOnly = false
Failed

Java 1.5.0 -> Test Passed.
$ jdk1.5.0/bin/java Bug4525475
LookAndFeel: com.sun.java.swing.plaf.windows.WindowsLookAndFeel
Name = Go Up, readOnly = true
Name = Go Up, readOnly = false
Name = New Folder, readOnly = false
Passed