* lisp/net/tramp-sh.el (tramp-set-remote-path): Replace "echo -n" by
"printf", it isn't portable.
* test/lisp/net/tramp-tests.el (tramp-test33-environment-variables)
(tramp-test33-environment-variables-and-port-numbers): Do not use
"echo -n", it isn't portable.
(tramp--test-utf8): Filter out not displayable characters.