ICU-22318 Fix bad spacing/formatting in utxttest.cpp

[pedberg-icu]

Checklist

• Required: Issue filed: https://unicode-org.atlassian.net/browse/ICU-22318
• Required: The PR title must be prefixed with a JIRA Issue number.
• Required: The PR description must include the link to the Jira Issue, for example by completing the URL in the first checklist item
• Required: Each commit message must be prefixed with a JIRA Issue number.
• Issue accepted (done by Technical Committee after discussion)
• Tests included, if applicable
• API docs and/or User Guide docs changed or added, if applicable

Fix bad spacing/formatting in utxttest.cpp resulting from PR #2382 (was supposed to fix typos but did not notice any, maybe they already got fixed under the minor docs fix ticket. This is a separate ticket because Markus originally asked me to make it one...)

[jira-pull-request-webhook]

Hooray! The files in the branch are the same across the force-push. 😃

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[roubert]

LGTM