Fix minor Tramp problems found on BSD

Fix minor Tramp problems found on BSD

* lisp/net/tramp-sh.el (tramp-perl-file-truename): Do not append
trailing slash.  Quote apostrophes.
(tramp-sh-handle-file-truename): Do not append trailing slash in
the "ls" case.
(tramp-get-ls-command-with-w-option): New defun.
(tramp-do-file-attributes-with-ls)
(tramp-do-directory-files-and-attributes-with-stat): Use it.

* test/automated/tramp-tests.el
(tramp-test31-special-characters-with-perl)
(tramp-test31-special-characters-with-ls)
(tramp-test32-utf8-with-perl, tramp-test32-utf8-with-ls):
Suppress also readlink.