bpo-40294: Fix _asyncio when module is loaded/unloaded multiple times (GH-19542)

(cherry picked from commit a75e730075cd25be1143e6183006f3b1d61bb80f)

Co-authored-by: Jeffrey Quesnelle <jquesnelle@gmail.com>
diff --git a/Modules/_asynciomodule.c b/Modules/_asynciomodule.c
index f4efa21..5ba2bc4 100644
--- a/Modules/_asynciomodule.c
+++ b/Modules/_asynciomodule.c
@@ -3261,6 +3261,8 @@
     Py_CLEAR(context_kwname);
 
     module_free_freelists();
+
+    module_initialized = 0;
 }
 
 static int