Fix unit tests by loading no translations by default in tests

config/environment/test.php

core/Intl/Locale.php

core/Translate.php

core/Translation/Translator.php

plugins/LanguagesManager/LanguagesManager.php

tests/PHPUnit/Unit/Metrics/Formatter/HtmlTest.php

tests/PHPUnit/Unit/Metrics/FormatterTest.php

tests/PHPUnit/Unit/Period/BasePeriodTest.php

tests/PHPUnit/Unit/Period/DayTest.php

tests/PHPUnit/Unit/Period/MonthTest.php

tests/PHPUnit/Unit/Period/RangeTest.php

tests/PHPUnit/Unit/Period/WeekTest.php

tests/PHPUnit/Unit/Period/YearTest.php

tests/PHPUnit/bootstrap.php