Since changeset 2582 portfiles are not required for running sjavac in background, thus the --server option should not be mandatory.

Also, if --server is provided, background=false makes no sense. The background-suboption should probably be dropped.

Finally, --server is of no use server-side. It makes little sense to pass this option on to the server. If the client removes this option, SjavacImpl (javac pass through mode) don't have to bother doing it.