.guile: Remove useless mytime macro.

Guile has `,time` which works way better.

.guile

@@ -18,9 +18,3 @@ convenient interactive line editing and input history.\n\n")))
               (else
                (display "Consider installing the 'guile-colorized' package
 for a colorful Guile experience.\n\n"))))
-
-;; TODO: Import (debugging time)
-(use-modules (debugging time))
-(define-macro (mytime expr . others)
-  `(let ((internal-time-units-per-second 1000000000.))
-     (time ,expr ,@others)))