gdb/

gdb/

	* tracepoint.c (TFILE_PID): Remove.
	(tfile_open): Don't add thread and inferior.
	(tfile_close): Don't set 'inferior_ptid'.  Don't call
	exit_inferior_silent.
	(tfile_thread_alive): Remove.
	(init_tfile_ops): Don't set field 'to_thread_alive' of
	tfile_ops.

gdb/testsuite/

	* gdb.trace/tfile.exp: Test inferior and thread.