Re-enable timing

original commit: a134ec73ed7f397eccc289f9163acd81c4553f0e

collects/typed-racket/utils/utils.rkt

@@ -111,7 +111,7 @@ at least theoretically.
       #'(void)))
 
 ;; some macros to do some timing, only when `timing?' is #t
-(define-for-syntax timing? #f)
+(define-for-syntax timing? #t)
 
 (define last-time #f) (define initial-time #f)
 (define (set!-initial-time t) (set! initial-time t))