issues with the qe_rec tactic

[zhendongsu]

OS: Ubuntu 18.04
Commit: 6c165e8

[570] % z3release small.smt2 
ASSERTION VIOLATION
File: ../src/math/simplex/model_based_opt.cpp
Line: 1655
UNEXPECTED CODE WAS REACHED.
Z3 4.11.1.0
Please file an issue with this message and more detail about how you encountered it at https://github.com/Z3Prover/z3/issues/new
[571] % cat small.smt2 
(assert (forall ((v Int)) (or (= 0 (div v 1)) (distinct 0 (mod v 2)))))
(check-sat-using qe_rec)

[zhendongsu]

Appears to be a hang:

[580] % timeout -s 9 30 z3release small.smt2 
Killed
[581] % cat small.smt2 
(assert (forall ((v Int)) (or (= 0 (mod v 2)) (= 0 (div v 2)))))
(check-sat-using qe_rec)