infrun: switch to NO_HISTORY thread

infrun: switch to NO_HISTORY thread

A thread that runs out of its execution history is stopped.  We already set
stop_pc and call stop_waiting.  But we do not switch to the stopped thread.

In normal_stop, we call finish_thread_state_cleanup to set a thread's running
state.  In all-stop mode, we call it with minus_one_ptid; in non-stop mode, we
only call it for inferior_ptid.

If in non-stop mode normal_stop is called on behalf of a thread that is not
inferior_ptid, that other thread will still be reported as running.  If it is
actually stopped it can't be resumed again.

Record targets traditionally don't support non-stop and only resume
inferior_ptid.  So this has not been a problem, so far.

Switch to the eventing thread for NO_HISTORY events as preparation to support
non-stop for the record btrace target.

gdb/
	* infrun.c (handle_inferior_event_1): Switch to the eventing thread
	in the TARKET_WAITKIND_NO_HISTORY case.