[jak3] Prevent NaN-induced infinite loop in ff-squad-control bubble sort (#4225)

This bit of ff-squad-control code is trying to sort guards based on
their distance from some shared target. In some cases the
`vector-vector-distance` returns NaN. In the bubble sort below this
change, the < operation always returns #t when NaN is involved, so the
NaN guard gets swapped back and forth endlessly, causing an infinite
loop.

goal_src/jak3/engine/math/math.gc

@@ -10,6 +10,9 @@
   `(.lvf vf0 (new 'static 'vector :x 0.0 :y 0.0 :z 0.0 :w 1.0))
   )
 
+(defmacro is-nan? (flt)
+  `(and (< 0.0 ,flt) (< ,flt 0.0)))
+
 ;; DECOMP BEGINS
 
 (defun truncate ((arg0 float))

goal_src/jak3/levels/city/common/ff-squad-control.gc

@@ -186,8 +186,12 @@
            (when (and s2-0 (not (focus-test? s2-0 dead inactive)) (= (-> s2-0 target-status handle) (-> arg2 handle)))
              (set! (-> sv-176 sv-184) s2-0)
              (set! (-> sv-180 sv-184) (vector-vector-distance (-> s2-0 root trans) (-> arg2 position)))
-             (set! sv-184 (+ sv-184 1))
-             (set! (-> s2-0 move-index) -1)
+             ;; og:preserve-this only add guard to the list if their distance isn't NaN
+             ;;   any < operation involving NaN will return #t, causing infinite loop in bubble sort below
+             (when (not (is-nan? (-> sv-180 sv-184)))
+              (set! sv-184 (+ sv-184 1))
+              (set! (-> s2-0 move-index) -1)
+              )
              )
            )
          )