Make test_comp_bisim complete in slightly less time

Locally, this shaves off about 10 seconds from the overall verification time,
and it should make this test case finish more reliably within the CI's time
limits.

intTests/test_comp_bisim/cryptol/spec.cry

@@ -6,19 +6,19 @@ type input  = feedback_input 16
 type output = feedback_output 16
 
 // add10 spec
-type add10_state  = feedback_state 16 8
+type add10_state  = feedback_state 16 4
 add10_spec : (add10_state, input) -> (add10_state, output)
 add10_spec = feedback_spec`{n=10} f
   where f x = x + 10
 
 // pow4 spec
-type pow4_state  = feedback_state 16 8
+type pow4_state  = feedback_state 16 3
 pow4_spec : (pow4_state, input) -> (pow4_state, output)
 pow4_spec = feedback_spec`{n=2} f
   where f x = x ^^ 4
 
 // comp spec
-type comp_spec_state = feedback_state 16 8
+type comp_spec_state = feedback_state 16 4
 comp_spec : (comp_spec_state, input) -> (comp_spec_state, output)
 comp_spec = feedback_spec `{n=13} f
   where f x = (x ^^ 4) + 10