conj!/assoc!/dissoc!/disj!/pop!/persistent! now throw on a non-transient (or
wrong transient kind) instead of falling back to the persistent op, matching
Clojure. conj! keeps its special arities: (conj!) -> (transient []), (conj! coll)
-> coll. conj! onto a transient map accepts a [k v] pair or a map (merge), and
throws on a list/set/seq.
pop_bang/dissoc_bang clean; conj_bang 13/1/22->47/3/1; persistent_bang 9/8->16/1.
clojure-test-suite pass 3781->3824. spec: transient/strictness (10). jpm test green.