edsp: if internal is used, keep this decision

edsp: if internal is used, keep this decision

It wasn't noticeable before, but now with the (optional) logging it can
be observed that we decide in the internal path two times if an internal
or external solver should be used (and hence with logging, it is
attempted twice), so if we are in the internal path call the internal
resolver directly, which means those internal methods need to be public
– but we can hide them based on the symbol at least.