Issue #16714: use 'raise' exceptions, don't 'throw'.

Patch by Serhiy Storchaka.
diff --git a/Lib/multiprocessing/util.py b/Lib/multiprocessing/util.py
index 20bba37..61b0533 100644
--- a/Lib/multiprocessing/util.py
+++ b/Lib/multiprocessing/util.py
@@ -301,7 +301,7 @@
         _run_finalizers(0)
         if current_process() is not None:
             # We check if the current process is None here because if
-            # it's None, any call to ``active_children()`` will throw an
+            # it's None, any call to ``active_children()`` will raise an
             # AttributeError (active_children winds up trying to get
             # attributes from util._current_process).  This happens in a
             # variety of shutdown circumstances that are not well-understood