Fix satNum
Fix satNum

Since SBV 7.0; allSat is no longer lazy. So, Cryptol's current
implementation is buggy:

   Cryptol> :set satNum=2
   Cryptol> :sat \x -> x >(3:Integer)
   .. Runs forever ..

This pull request fixes the issue:

   Cryptol> :set satNum=2
   Cryptol> :sat \x -> x>(3:Integer)
   (\x -> x > (3 : Integer)) 4 = True
   (\x -> x > (3 : Integer)) 5 = True
   (Total Elapsed Time: 0.000s, using Z3)

Note that if you set `satNum` to be `all` and if there are indeed an
infinite number of satisfying models, SBV (and thus Cryptol) will still
loop forever. There's really no good way to solve that problem,
unfortunately.

GaloisInc/cryptol,GaloisInc/cryptol,GaloisInc/cryptol