Make all Tramp tests pass for "gdrive" method

Make all Tramp tests pass for "gdrive" method

* lisp/net/tramp-gvfs.el (tramp-gvfs-handle-delete-directory)
* lisp/net/tramp-compat.el (tramp-compat-copy-directory)
(tramp-compat-delete-directory):
* lisp/net/tramp-smb.el (tramp-smb-handle-delete-directory):
Use `directory-files-no-dot-files-regexp'.

* lisp/net/tramp-gvfs.el (tramp-gvfs-handler-mounted-unmounted)
(tramp-gvfs-send-command): Call `tramp-flush-file-property' in
case of problems.

* test/lisp/net/tramp-tests.el (tramp--instrument-test-case):
Adapt docstring.
(tramp-test14-delete-directory): Make further tests.