This is something that should be the responsibility of the frontend
booting the game. Making this part of the host 'interface' inherently
requires frontends to leak internal details (much like the other
UI-related functions in the interface).
This also decouples more behavior from the debugger and the
initialization process in the wx frontend. This also eliminates several
usages of the parent menubar in the debugger code window.
EndPlayInput runs on the CPU thread so it can't directly call
UpdateWantDeterminism. PlayController also tries to ChangeDisc
from the CPU Thread which is also invalid. It now just pauses
execution and posts a request to the Host to fix it instead.
The Core itself also did dodgy things like PauseAndLock-ing
from the CPU Thread and SetState from EmuThread which have been
removed.
