ARROW-15795: [Java] Add a getter for the timeZone in timestamp with timezone vectors

[fabiencelier]

https://issues.apache.org/jira/browse/ARROW-15795

I have added an abstract class for all the timestamp vectors with timezone

[github-actions]

https://issues.apache.org/jira/browse/ARROW-15795

[github-actions]

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[fabiencelier]

Let me know if there is anything else I can do for this PR

[BryanCutler]

@fabiencelier we have tended to have a some code duplication to reduce class bloat for vectors, so I would prefer not to add an abstract class for this. You could get the timezone from a vector with

String tz = ((ArrowType.Timestamp) vector.getField().getFieldType().getType()).getTimezone();

which isn't pretty, so if you'd like to add a convenience method that does this in each of the timestamp with timezone vector classes, I think that would be ok.

[fabiencelier]

Hello @BryanCutler

Thanks for your feedback on this ! I have reverted the change introducing an abstract class and simply added a getter for the time zone in the 4 vectors with timezone.

[BryanCutler]

LGTM

[BryanCutler]

Test failures look unrelated, merging to master. Thanks @fabiencelier !

[ursabot]

Benchmark runs are scheduled for baseline = 348057a and contender = 6734d0f. 6734d0f 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
[Finished ⬇️0.42% ⬆️0.04%] test-mac-arm
[Finished ⬇️1.07% ⬆️0.0%] ursa-i9-9960x
[Finished ⬇️0.26% ⬆️0.09%] ursa-thinkcentre-m75q
Supported benchmarks:
ec2-t3-xlarge-us-east-2: Supported benchmark langs: Python. 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