fix benchmark/help

TODO.FACTOR.txt

@@ -9,6 +9,7 @@
 
 + ui:
 
+- "benchmark/help" runs out of memory
 - shortcuts:
   - find a listener
   - find a browser

library/test/benchmark/help.factor

@@ -3,9 +3,9 @@ sequences test threads words ;
 
 [
     all-articles [
-        stdio get pane-clear
+        stdio get duplex-stream-out pane-clear
         dup global [ . flush ] bind
         [ dup help ] assert-depth drop
-        yield
+        1 sleep
     ] each
 ] time