lower this so we don't timeout

test/tests/file_destructor.py

@@ -5,7 +5,7 @@ except e:
   pass
 
 def open_lots_of_files():
-  for x in range(0, 10000):
+  for x in range(0, 5000):
     f = open("/dev/null")
     if have_gc:
       gc.collect();