Support using the vCont packet to resume multiple processes
simultaneously when in non-stop mode. The new logic now assumes that:
- actions without a thread-id or with process id of "p-1" apply to all debugged processes
- actions with a thread-id without process id apply to the current process (m_continue_process)
As with the other continue packets, it is only possible to resume
processes that are currently stopped (or stop these that are running).
It is unsupported to resume or stop individual threads of a running
Sponsored by: The FreeBSD Foundation