py3: prove hg tip works

tests/test-check-py3-commands.t

@@ -51,6 +51,17 out some potential warnings that come fr
   \s*14 (re)
   $ $PYTHON3 $HGBIN files | wc -l
   \s*15 (re)
+
+Test if `hg tip` works:
+
+  $ $PYTHON3 $HGBIN tip
+  changeset:   10:e76ed1e480ef
+  tag:         tip
+  user:        [e-mail]
+  date:        Tue May 03 23:37:43 2005 -0800
+  summary:     Fix linking of changeset revs when merging
+  
+
   $ cd ..
 #endif