Some tweaks, almost all for Tramp adb method

Some tweaks, almost all for Tramp adb method

* lisp/net/tramp-adb.el (tramp-adb-parse-device-names):
Use `make-tramp-file-name'.
(tramp-adb-get-device): Use `tramp-file-name-port-or-default'.
(tramp-adb-maybe-open-connection): Set "prompt" property.
(tramp-adb-wait-for-output): Use it.

* lisp/net/tramp-cache.el (tramp-cache-print): Use `elt'.
(tramp-dump-connection-properties): Check also that there are
properties to be saved.  Don't save "started" property of
"ftp" method.

* lisp/net/tramp-gvfs.el (tramp-gvfs-handle-expand-file-name):
Use `make-tramp-file-name'.

* lisp/net/tramp.el (tramp-remote-file-name-spec-regexp):
Host could be empty.
(tramp-file-name-port-or-default): New defun.
(tramp-dissect-file-name): Simplify `make-tramp-file-name' call.
(tramp-handle-file-name-case-insensitive-p): Use a progress reporter.
(tramp-call-process, tramp-call-process-region):
Use `make-tramp-file-name'.

* test/lisp/net/tramp-tests.el (tramp-test03-file-name-defaults):
Revert change from 2017-05-24.
(tramp-test05-expand-file-name-relative): Let it also pass for
"adb" method.