Remove create_function from preg_replace_callback to improve memory usage

[nacin]

On large imports, a create_function() call in wp_kses_split() in particular causes memory issues pretty quickly.

Let's continue to move away from create_function calls as callbacks. Patch attached handles most instances.

[hakre]

Maybe using a static function does the job as well and saving the global namespace function starting with subjective stuff like funky? Not that I like create_function that much, but well, it was in use anyway and it's for this callback only.

Second patch looks being an upload in error.

[hakre]

Just added a patch that solves the reported memory issue. Compared to Nacins suggestion it does not re-introduced an already deprecated function (!) nor does it change the existing function header of wp_kses_split2().

[hakre]

Memory Related: #13847

[nacin]

I don't have a problem with re-introducing a function I myself deprecated. It serves its original purpose. Why not?

[nacin]

Both handled elsewhere.