[Core] Fix platform dependent unit tests

[kgeilmann]

Is your pull request related to a problem? Please describe.

Fixing the encoding related problems in tests of #2104

Describe the solution you have implemented

BannerTest, NoPublishFormatterTest, UrlReporterTest:
Using UTF-8 encoding in tests instead of relying on default encoding of the system, because otherwise the non-ascii characters are destroyed.

CommandLineOptionsParserTest:
Removed the line endings from the comparision, so moving to the same behaviour as other non-failing tests of the same class.

Additional context

[coveralls]

Coverage remained the same at 86.481% when pulling 608231b on kgeilmann:fix_unittests_#2104 into bb97c69 on cucumber:main.

[aslakhellesoy]

Hi @kgeilmann,

Thanks for your making your first contribution to Cucumber, and welcome to the Cucumber committers team! You can now push directly to this repo and all other repos under the cucumber organization! 🍾

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Aslak Hellesøy
Creator of Cucumber

[mpkorstanje]

Cheers!