ORC-1681: Remove redundant import statement in tests to fix checkstyle failures

[dongjoon-hyun]

What changes were proposed in this pull request?

This is a kind of follow-up of the following to remove redundant import statement in tests to fix checkstyle failure.

• https://github.com/apache/orc/pull/1871
• https://github.com/apache/orc/pull/1870

Why are the changes needed?

To recover CIs.

How was this patch tested?

Pass the CIs.

Was this patch authored or co-authored using generative AI tooling?

No.

[dongjoon-hyun]

Could you review this too, @williamhyun ?

[williamhyun]

Merged, will be closing this now.

[dongjoon-hyun]

Thank you so much, @williamhyun !