- Remove Universe Polymorphism flags everywhere.
- Properly infer, discharge template arities and fix substitution inside them
(kernel code to check for correctness).
- Fix tactics that were supposing universe polymorphic constants/inductives to
be parametric on that status. Required to make interp_constr* return the whole evar
universe context now.
- Fix the univ/level/instance hashconsing to respect the fact that marshalling doesn't preserve sharing,
sadly losing most of its benefits.
Short-term solution is to add hashes to these for faster comparison, longer term requires rewriting
all serialization code.