Use the --timeout flag to change the timeout.
--timeout
herbie shell --seed 2019088 (FPCore (u1 u2) :name "normal distribution" :pre (and (<= 0 u1 1) (<= 0 u2 1)) (+ (* (* (/ 1 6) (pow (* -2 (log u1)) 0.5)) (cos (* (* 2 PI) u2))) 0.5))