Some Tramp fixes for directory-files-* and delete-*

Some Tramp fixes for directory-files-* and delete-*

* lisp/files.el (delete-directory): Simplify check for trash.

* lisp/net/ange-ftp.el (ange-ftp-delete-file): Implement TRASH.

* lisp/net/tramp-compat.el (tramp-compat-directory-files)
(tramp-compat-directory-files-and-attributes)
(tramp-compat-directory-empty-p): New defaliases.

* lisp/net/tramp.el (tramp-handle-directory-files-and-attributes)
(tramp-skeleton-delete-directory):
* lisp/net/tramp-gvfs.el (tramp-gvfs-handle-delete-directory): Use them.

* lisp/net/tramp-sh.el (tramp-sh-handle-directory-files-and-attributes):
Implement COUNT.

* test/lisp/net/tramp-tests.el (tramp-test14-delete-directory):
Do not run trash test for ange-ftp.
(tramp-test16-directory-files)
(tramp-test19-directory-files-and-attributes): Check COUNT argument.