[core] Fix qlaunch crash on second launch (#3930)

partial revert [08232ce642](08232ce642)

Reviewed-on: https://git.eden-emu.dev/eden-emu/eden/pulls/3930
Reviewed-by: Lizzie <lizzie@eden-emu.dev>
Reviewed-by: MaranBr <maranbr@eden-emu.dev>

src/core/core.cpp

@@ -415,7 +415,6 @@ struct System::Impl {
         cpu_manager.Shutdown();
         debugger.reset();
         kernel.Shutdown();
-        device_memory.reset();
         stop_event = {};
         Network::RestartSocketOperations();