Unicode-Tests are partially local-dependent

[Akron]

In a server environment (head-01) the test suite returns the following error:

t/plugin/auth-oauth.t .......... 43/? 
#   Failed test 'exact match for attribute "title" at selector "a.logout"'
#   at t/plugin/auth-oauth.t line 472.
#          got: 'Logout: t�st'
#     expected: 'Logout: täst'
t/plugin/auth-oauth.t .......... 394/? # Looks like you failed 1 test of 581.
t/plugin/auth-oauth.t .......... Dubious, test returned 1 (wstat 256, 0x100)
Failed 1/581 subtests 
t/plugin/conllu2korapxml.t ..... ok   

$LANG is correctly set to de_DE.UTF-8 and the test script uses UTF-8. So there may be a problem with the file encoding.

[Akron]

This now breaks CI and can therefore be considered urgent.