ARROW-18178: [Java] ArrowVectorIterator incorrectly closes Vectors

[lwhite1]

Prevent vectors from being closed when ArrowVectorIterator closes in the case where the reuseVectorSchemaRoot flag is set to false.

Test in JDBCToArrowVectorIteratorTest was updated to cover this case.

Tests in UnreliableMetaDataTest were modified to manually close VectorSchemaRoots, preventing an unclosed buffer exception being thrown when the RootAllocator was closed.

[lwhite1]

@lidavidm If you could review that would be helpful

[github-actions]

https://issues.apache.org/jira/browse/ARROW-18178

[github-actions]

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[lidavidm]

LGTM.

Is there somewhere in the Javadocs or prose docs that this behavior should be described? (That is: if the VSR is reused, closing the iterator closes the root as expected; else the caller is expected to manage all roots)

[lwhite1]

LGTM.

Is there somewhere in the Javadocs or prose docs that this behavior should be described? (That is: if the VSR is reused, closing the iterator closes the root as expected; else the caller is expected to manage all roots)

Good catch. It is mentioned in the method javadoc for next(). I just pushed a commit that makes it explicit in the close() method.

[ursabot]

Benchmark runs are scheduled for baseline = 9f4c632 and contender = f57ad93. f57ad93 is a master commit associated with this PR. Results will be available as each benchmark for each run completes.
Conbench compare runs links:
[Finished ⬇️0.0% ⬆️0.0%] ec2-t3-xlarge-us-east-2
[Failed ⬇️0.0% ⬆️0.0%] test-mac-arm
[Finished ⬇️1.9% ⬆️0.0%] ursa-i9-9960x
[Finished ⬇️0.18% ⬆️0.0%] ursa-thinkcentre-m75q
Buildkite builds:
[Finished] f57ad932 ec2-t3-xlarge-us-east-2
[Failed] f57ad932 test-mac-arm
[Finished] f57ad932 ursa-i9-9960x
[Finished] f57ad932 ursa-thinkcentre-m75q
[Finished] 9f4c632f ec2-t3-xlarge-us-east-2
[Failed] 9f4c632f test-mac-arm
[Finished] 9f4c632f ursa-i9-9960x
[Finished] 9f4c632f ursa-thinkcentre-m75q
Supported benchmarks:
ec2-t3-xlarge-us-east-2: Supported benchmark langs: Python, R. Runs only benchmarks with cloud = True
test-mac-arm: Supported benchmark langs: C++, Python, R
ursa-i9-9960x: Supported benchmark langs: Python, R, JavaScript
ursa-thinkcentre-m75q: Supported benchmark langs: C++, Java

[ursabot]

['Python', 'R'] benchmarks have high level of regressions.
ursa-i9-9960x