Fix minor problems resulting from Tramp regression tests

Fix minor problems resulting from Tramp regression tests

* lisp/net/tramp-adb.el (tramp-adb-file-name-handler-alist):
* lisp/net/tramp-archive.el (tramp-archive-file-name-handler-alist):
* lisp/net/tramp-crypt.el (tramp-crypt-file-name-handler-alist):
* lisp/net/tramp-gvfs.el (tramp-gvfs-file-name-handler-alist):
* lisp/net/tramp-rclone.el (tramp-rclone-file-name-handler-alist):
* lisp/net/tramp-sshfs.el (tramp-sshfs-file-name-handler-alist):
Add comment.

* lisp/net/tramp-cache.el (tramp-flush-file-upper-properties):
FILE can be "~".

* lisp/net/tramp.el ('tramp-ensure-dissected-file-name):
Add `tramp-suppress-trace' property.
(tramp-get-debug-buffer): Add local key for debugging.
(tramp-handle-abbreviate-file-name): Adapt implementation.

* test/lisp/net/tramp-tests.el
(tramp-test07-abbreviate-file-name):
Adapt test.
(tramp-test17-insert-directory-one-file)
(tramp--test-check-files): Use proper `no-dir' argument for
`dired-get-filename'.