determinise: Adjust SMALL_INPUT_LIMIT.

I benchmarked with a range of values 8 to 4096, somewhere around
32 - 256 worked particularly well, and it started to become slower
beyond that, so set it to <32 for now.

src/libfsm/determinise.c

@@ -2065,7 +2065,7 @@ cmp_fsm_state_t(const void *pa, const void *pb)
 	return a < b ? -1 : a > b ? 1 : 0;
 }
 
-#define SMALL_INPUT_LIMIT 15
+#define SMALL_INPUT_LIMIT 255
 #define SMALL_INPUT_CHECK 0
 
 #ifdef SMALL_INPUT_LIMIT