test: fold ported-clojure batteries into spec

Mine the remaining integration 'ported Clojure' batteries into the spec layer
and delete them (clojure-atom/control/for/logic/macros, core, logic). A broad
function-coverage diff confirmed they exercised no clojure.core fn the spec
lacked; their distinctive value was the truthiness/boolean contract, now
captured in a dedicated spec.

New/expanded spec coverage:
- spec/truthiness-spec: only nil/false are falsy (0, "", [], {}, #{} are truthy);
  not / and / or return-value & short-circuit semantics; if-not/when-not/boolean
- assert (exceptions-spec), get-validator (state-spec)

Layout now: spec 23 files / 732 cases; integration trimmed to 10 genuine
cross-cutting batteries (conformance, SCI bootstrap/runtime, jank, compile-mode,
api, namespace, bootstrap, features, systematic-coverage). conformance 218/218,
jpm test green.

test/spec/exceptions-spec.janet

@@ -17,6 +17,12 @@
   ["catch value of body" "5"
    "(try (+ 2 3) (catch :default e 0))"])
 
+(defspec "exceptions / assert"
+  ["assert true -> ok"   ":ok"    "(do (assert true) :ok)"]
+  ["assert expr -> ok"   ":ok"    "(do (assert (= 1 1)) :ok)"]
+  ["assert false throws" :throws  "(assert false)"]
+  ["assert nil throws"   :throws  "(assert nil)"])
+
 (defspec "exceptions / ex-info"
   ["ex-message"          "\"oops\""  "(ex-message (ex-info \"oops\" {}))"]
   ["ex-data"             "{:k 1}"    "(ex-data (ex-info \"oops\" {:k 1}))"]