Tree profilng merge 8 - make cfg build debug info friendly

[Steven Bosscher]

> *************** init_tree_optimization_passes (void)
> *** 275,280 ****
> --- 275,281 ----
>     *p = NULL;
>   
>     p = &pass_all_optimizations.sub;
> +   NEXT_PASS (pass_cleanup_cfg);
>     NEXT_PASS (pass_build_cfg);
>     NEXT_PASS (pass_tree_profile);
>     NEXT_PASS (pass_referenced_vars);

This "cleanup before build" could use a comment ;-)

Gr.
Steven