assume the presence of gc.collect. gc.collect() every 80 iterations

test/tests/file_destructor.py

-try:
-  import gc
-  have_gc = True
-except e:
-  pass
+import gc
 
 def open_lots_of_files():
-  for x in range(0, 5000):
-    f = open("/dev/null")
-    if have_gc:
-      gc.collect();
+    for x in range(0, 10000):
+        f = open("/dev/null")
+        if x % 80 == 0:
+            gc.collect();
 
 open_lots_of_files()