Limit hashconsing to apron domain if it is undesired globally instead of refusing to run

[michael-schwarz]

As to the Apron domain use case (getting a totally-ordered compare for a type with just equal and hash), a thing to explore could also be wrapping hashconsing directly around that domain, instead of relying on some very outermost hashconsing to implement compare such that Goblint wouldn't crash outright.

Originally posted by @sim642 in #1657