[tests] Fix constant pi value.

tests/interpretation_acasxu.t

@@ -33,7 +33,7 @@ Test interpret on acasxu
   >   constant strong_left: action = 3
   >   constant strong_right: action = 4
   > 
-  >   constant pi: t = 3.141592999999999857863031138549558818340301513671875
+  >   constant pi: t = 3.141592653589793115997963468544185161590576171875000
   > 
   >   predicate valid_input (i: input) =
   >     (0.0:t) .<= i[distance_to_intruder] .<= (60760.0:t)