glsl: Remove ir_print_visitor.h includes and usage

glsl: Remove ir_print_visitor.h includes and usage

We have ir->print() to do the old declaration of a visitor and having the
IR accept the visitor (yuck!).  And now you can call _mesa_print_ir()
safely anywhere that you know what an ir_instruction is.

A couple of missing printf("\n")s are added in error paths -- when an
expression is handed to the visitor, it doesn't print '\n' (since it might
be a step in printing a whole expression tree).

Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Paul Berry <stereotype441@gmail.com>