CryptolTC.z3: Don't bother defining a prime table

`prime` is usually called on large primes, so it's not worth the effort of
defining a lookup table for small prime numbers. Either way, this is unlikely
to have a noticeable effect on performance.

lib/CryptolTC.z3

@@ -78,17 +78,9 @@
 
 (declare-fun cryPrimeUnknown (Int) Bool)
 
-(define-fun cryPrimeTable ((x Int)) Bool
-  (or (= x 2)
-  (or (= x 3)
-  (or (= x 5)
-  (or (= x 7)
-  (cryPrimeUnknown x)))))
-)
-
 (define-fun cryPrime ((x InfNat)) MaybeBool
   (ite (isErr x) cryErrProp
-    (cryBool (and (isFin x) (cryPrimeTable (value x)))))
+    (cryBool (and (isFin x) (cryPrimeUnknown (value x)))))
 )