ICU-22833 Port ICU 74.2 to Oracle Studio 12.6

[scott-zhong]

Checklist

• Required: Issue filed: https://unicode-org.atlassian.net/browse/ICU-22833
• 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

ICU-22833 Port ICU 74.2 to Oracle Studio 12.6

[CLAassistant]

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[markusicu]

@scott-zhong could you please sign the CLA? Otherwise we can't look at your contribution.