ARROW-16547: [Python] to_pandas fails with FixedOffset timezones when timestamp_as_object is used

[AlenkaF]

This PR tries to substitute fromutc method in ConvertTimezoneAware (arrow_to_pandas.cc) as it errors when tzinfo is an instance of pytz timezone. Basically does the change from:

tzinfo.fromutc(dt)

to

dt.replace(tzinfo=datetime.timezone.utc).astimezone(tzinfo)

but in C++.

Thank you @milesgranger for the help!

[github-actions]

https://issues.apache.org/jira/browse/ARROW-16547

[github-actions]

⚠️ Ticket has not been started in JIRA, please click 'Start Progress'.

[AlenkaF]

Ha, I am getting the strange behaviour on CI now (not locally):
https://github.com/apache/arrow/actions/runs/3280427766/jobs/5401187533#step:6:5793

Edit: actually I think the expected df is wrong - need to look into that.

[jorisvandenbossche]

Looks good!

[jorisvandenbossche]

The remaining failures are ones are known ones, so merging!

[ursabot]

Benchmark runs are scheduled for baseline = c56934b and contender = 31e8eeb. 31e8eeb 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 ⬇️0.82% ⬆️0.0%] ursa-i9-9960x
[Finished ⬇️0.07% ⬆️0.04%] ursa-thinkcentre-m75q
Buildkite builds:
[Finished] 31e8eebd ec2-t3-xlarge-us-east-2
[Failed] 31e8eebd test-mac-arm
[Finished] 31e8eebd ursa-i9-9960x
[Finished] 31e8eebd ursa-thinkcentre-m75q
[Finished] c56934b5 ec2-t3-xlarge-us-east-2
[Failed] c56934b5 test-mac-arm
[Finished] c56934b5 ursa-i9-9960x
[Finished] c56934b5 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