Consider exposing all functions taking a dictionary argument.

This should allow SPECIALIZE to succeed more often without having to rely on the the sledgehammer that is -fexpose-all-unfoldings.

It's still far from perfect but seems like a reasonable change. I wrote up a small poc here !9940 (closed) which always exposes such overloaded bindings. Alternatively this could also be hidden behind a flag and perhaps implied by -O2/-fspecialise-aggressively.