Code review request for 6888546

[Mandy Chung]

  Hi Alan,

Can you review the fix for:
    6888546: restore System.initializeSystemClasses

Webrev at:
    http://cr.openjdk.java.net/~mchung/6888546/webrev.00/

With the fix for 6612680, the download manager won't start until the VM 
completes its initialization.  This is to remove the workaround added 
for jkernel in the fix for 6797688.

Thanks
Mandy