Issue #2323521 by herom: Fixed a couple of t() calls in core.

core/lib/Drupal/Core/Database/Driver/pgsql/Install/Tasks.php

core/modules/file/file.field.inc

core/modules/image/src/Tests/ImageFieldDisplayTest.php

core/modules/image/src/Tests/ImageFieldValidateTest.php

core/modules/system/src/Tests/Entity/FieldSqlStorageTest.php

core/modules/system/src/Tests/Form/FormTest.php

core/modules/system/src/Tests/System/DateTimeTest.php