Get rid of the direct_output optimizations.

Get rid of the direct_output optimizations.
* keyboard.c (nonundocount): Remove extern declaration.
(command_loop_1): Remove brittle optimisation for cheap and common operations.
* xdisp.c (redisplay_internal): Don't bother checking
redisplay_performed_directly_p any more.
* sysdep.c (init_sys_modes): Don't call direct_output_forward_char any more.
* dispnew.c (redisplay_performed_directly_p)
(direct_output_for_insert, direct_output_forward_char):
* dispextern.h (redisplay_performed_directly_p)
(direct_output_for_insert, direct_output_forward_char): Remove.
* cmds.c (nonundocount): Make it static.