[GDB] exit bug #2

[kas1e]

Even with disable threading, we again meet in some condition with the same blocked gdb console and same window about "child/parent process". This happens when we start to debug anything, breaks, and type exit (to break debugging and exit).

To reproduce:

compile simple test case
run it into gdb
break on main
run
and now, while we breaks, type "exit"

as a result we have this window about "child/parent" process, and in the gdb console that:

A debugging session is active
             Inferior 1 [process 162897824] will be killed.

Quit anyway ? (y or no) y
You can't do that without a process to debug.

[kas1e]

This one fixed, thanks!