"Detach Debugger" menu kills the process instead of detaching from it

To reproduce:

1. Make a new project, with code containing an infinite loop
2. Set breakpoint at main, start debugger
3. Make sure the process can be seen via something like ps -A|grep test
4. Choose menu Debug → Detach Debugger
5. Check once again for the process as in step 3, see it's gone

If you instead issued detach command in the Debugger Log, this would work as expected: the debugger (GDB) is no longer attached to the process, debugging session has ended, and the process lives on.

Qt Creator's Detach Debugger menu also shouldn't kill the inferior.