Revision 7e79421 (issue #484) makes emulator.cc rejecting any unrecognized
+arg "legacy" arguments, however, this breaks riscv-torture emulator tests
as it needs to pass +signature to the DTM.
I think it is actually impossible to check for unknown argument here
unless we hardcode a list of all arguments recognized by fesrv. Fix this
issue by passing all arguments starting with the first unknown argument
to DTM.
Updates #484.
Signed-off-by: Minux Ma <minux.ma@gmail.com>
622e311962