Fix various problems in Tramp

Fix various problems in Tramp

* lisp/net/tramp-compat.el (tramp-temp-name-prefix): Declare.
(tramp-compat-make-temp-name):
* lisp/net/tramp.el (tramp-make-tramp-temp-name): New defuns.

* lisp/net/tramp.el (tramp-make-tramp-temp-file):
* lisp/net/tramp-sh.el (tramp-find-inline-encoding)
(tramp-maybe-open-connection, tramp-get-remote-touch)
(tramp-get-remote-chmod-h):
* lisp/net/tramp-smb.el (tramp-smb-handle-copy-directory): Use them.

* lisp/net/tramp-sh.el (tramp-do-file-attributes-with-stat):
Simplify shell command.  Suppress errors (interpret as nil).
(tramp-sh-handle-make-process): Do not visit with
`insert-file-contents'.  Delete tmp file only if exists.
(tramp-send-command-and-read): Suppress `signal-hook-function'
when reading expression.