core: hle: kernel: k_process: DisableDispatch on main thread.

src/core/hle/kernel/k_process.cpp

@@ -60,6 +60,7 @@ void SetupMainThread(Core::System& system, KProcess& owner_process, u32 priority
     thread->GetContext64().cpu_registers[0] = 0;
     thread->GetContext32().cpu_registers[1] = thread_handle;
     thread->GetContext64().cpu_registers[1] = thread_handle;
+    thread->DisableDispatch();
 
     auto& kernel = system.Kernel();
     // Threads by default are dormant, wake up the main thread so it runs when the scheduler fires