Tramp: Do not raise an error when not connected (Bug#78572)

Tramp: Do not raise an error when not connected  (Bug#78572)

* lisp/net/tramp-cmds.el (tramp-cleanup-connection):
Use read syntax #' for `tramp-timeout-session',

* lisp/net/tramp.el (tramp-barf-if-file-missing): Do not raise an error
when not connected.  (Bug#78572)
(tramp-file-name-handler): Do not force the backtrace.
(tramp-connectable-p): Check also, whether initial handshake is finished.
(tramp-skeleton-directory-files)
(tramp-skeleton-directory-files-and-attributes)
(tramp-skeleton-set-file-modes-times-uid-gid): Rearrange sending
`file-missing' error.
(tramp-handle-access-file, tramp-handle-unlock-file):
Use `tramp-connectable-p'.

* test/lisp/net/tramp-tests.el (project-mode-line-format)
(project-mode-line): Declare.
(tramp-test48-session-timeout): New test.
(tramp-test49-auto-load, tramp-test49-delay-load)
(tramp-test49-recursive-load, tramp-test49-remote-load-path)
(tramp-test50-without-remote-files, tramp-test51-unload): Rename.

(cherry picked from commit 55691c61d4af972b999bb97bffb46cb8571c912c)