GH-43320: [Java] fix for SchemaChangeRuntimeException transferring empty FixedSizeListVector

[jarohen]

What changes are included in this PR?

When we create a FSLV through TransferImpl, we check to see if the source's element vector is a ZeroVector and, if not, we don't call addOrGetVector.

Are these changes tested?

Yep - see TestFixedSizeListVector

Are there any user-facing changes?

No

• GitHub Issue: [Java] SchemaChangeRuntimeException in transferred empty FixedSizeListVector #43320

[github-actions]

⚠️ GitHub issue #43320 has been automatically assigned in GitHub to PR creator.

[vibhatha]

There is a formatting error, this should have failed when compiling locally? mvn spotless:apply

[vibhatha]

Adding a test case to check the mentioned steps in the issue would be better.

[jarohen]

There is a formatting error, this should have failed when compiling locally? mvn spotless:apply

@vibhatha I did mvn -pl vector test which passed (although we're based atop the 17.0.0 release tag, so it might have changed in the meantime). In any event, will fix this up 🙏

Adding a test case to check the mentioned steps in the issue would be better.

I can, although this test case was a more minimal repro which took DUV out of the loop - it failed before the fix and passed afterwards.

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