Update Android port

Update Android port

* java/org/gnu/emacs/EmacsSafThread.java (CacheToplevel):
(EmacsSafThread):
(DocIdEntry):
(getCache):
(pruneCache):
(cacheDirectoryFromCursor):
(run):
(documentIdFromName1):
(statDocument1):
(openDocumentDirectory1):
(openDocument1): Introduce a file status cache and populate
it with files within directories as they are opened.
* java/org/gnu/emacs/EmacsService.java (createDocument):
(createDirectory):
(moveDocument): Invalidate the file status cache wherever
needed.
* src/fileio.c (check_vfs_filename):
(Fset_file_modes): Permit `set-file-modes' to silently fail
on asset and content files.