Kernel: Separate scheduler execution and stack loading

Not sure if this is actually needed, but this allows actual
executing function to be in clean environment

kernel/include/kernel/Scheduler.h

@@ -31,6 +31,7 @@ namespace Kernel
 		static bool is_valid_tid(pid_t tid);
 
 		[[noreturn]] void execute_current_thread();
+		[[noreturn]] void _execute_current_thread();
 		[[noreturn]] void delete_current_process_and_thread();
 
 	private: