(inst? x)
Return true if x satisfies Inst
(inst? (java.util.Date.))
;;=> true
(inst? (java.util.Calendar/getInstance))
;;=> false
(inst? (java.sql.Timestamp. 0))
;;=> true
(inst? (java.sql.Date. 0))
;;=> true
(inst? (java.time.Instant/now))
;;=> true
(inst? (java.time.LocalDateTime/now))
;;=> false