bpo-37316: mmap.mmap() passes the wrong variable to PySys_Audit() (GH-14152)

Also, add a missing call to va_end() in PySys_Audit().
diff --git a/Lib/test/test_audit.py b/Lib/test/test_audit.py
index f629b7b..2fc41bd 100644
--- a/Lib/test/test_audit.py
+++ b/Lib/test/test_audit.py
@@ -74,6 +74,9 @@
     def test_cantrace(self):
         self.do_test("test_cantrace")
 
+    def test_mmap(self):
+        self.do_test("test_mmap")
+
 
 if __name__ == "__main__":
     unittest.main()