glsl: Remove anti-built-in hacks from the print visitor.

Now that we only import built-in signatures that are actually used,
printing them is reasonable.

src/glsl/ir_print_visitor.cpp

@@ -153,17 +153,10 @@ void ir_print_visitor::visit(ir_function_signature *ir)
 
 void ir_print_visitor::visit(ir_function *ir)
 {
-   if (!ir->has_user_signature())
-      return;
-
    printf("(function %s\n", ir->name);
    indentation++;
    foreach_iter(exec_list_iterator, iter, *ir) {
       ir_function_signature *const sig = (ir_function_signature *) iter.get();
-
-      if (sig->is_builtin)
-	 continue;
-
       indent();
       sig->accept(this);
       printf("\n");