6595678 : java kernel jre completion should be done by jbroker on vista
Currently, after all kernel bundles are downloaded, the final JRE completion is triggered by the java launcher. It will call preJVMStart() in kernel.cpp to do the final clean up.
On Vista, preJVMStart will fail for normal user, because it needs to move files around in "program files" directory, and needs high IL to do so. So we need to have jbroker.exe to execute preJVMStart at high IL instead.