tests: update DispVM test
tests: update DispVM test

Apparently 'l' and 'n' characters aren't passed correctly by xdotool
(some keymap problem?). Do not use them in test text.

woju/qubes-core-admin,woju/qubes-core-admin,marmarek/qubes-core-admin,QubesOS/qubes-core-admin,QubesOS/qubes-core-admin,woju/qubes-core-admin,marmarek/qubes-core-admin,woju/qubes-core-admin,marmarek/qubes-core-admin,QubesOS/qubes-core-admin