upgrade: do not hardcore file extension of revlogs

This logic already lives inside the `store` module. So lets reuse it instead.

Differential Revision: https://phab.mercurial-scm.org/D10317

mercurial/upgrade_utils/engine.py

@@ -390,7 +390,7 b' def _files_to_copy_post_revlog_clone(src'
     are cloned"""
     for path, kind, st in sorted(srcrepo.store.vfs.readdir(b'', stat=True)):
         # don't copy revlogs as they are already cloned
-        if path.endswith((b'.i', b'.d', b'.n', b'.nd')):
+        if store.revlog_type(path) is not None:
             continue
         # Skip transaction related files.
         if path.startswith(b'undo'):