ARROW-17066: [C++][Python][Substrait] "ignore_unknown_fields" should be specified when converting JSON to binary

[vibhatha]

Substrait is continously changing and it introduces may unknown fields in the consumed plan. Since it is not practical to support all these fields simultaneously, we have to include a way to ignore such fields. To support that, the ignore_unknown_fields is added to the JsonParseOptions.

[vibhatha]

cc @westonpace

Not exactly sure if this is the expected fix. I may need some help to figure out a better test case too.
Please advise.

[github-actions]

https://issues.apache.org/jira/browse/ARROW-17066

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[vibhatha]

Need to figure out a better way to represent substrait plans in strings.

[richtia]

I'll try to test it out using your branch

[richtia]

I tried your branch, but since it also has the latest substrait now, i'm actually hitting some other issues, that Weston will be fixing. ARROW-15582/ARROW-15538

[pitrou]

@vibhatha Can you update the PR description since it will end up as the commit message?

[vibhatha]

@pitrou Sure I will update it.

[vibhatha]

@pitrou Updated the description.
@westonpace removed the todo comment.

[pitrou]

@vibhatha Well, can you make the PR description actually descriptive, instead of merely repeting the PR title? Thanks :-)

[pitrou]

i.e., explain why this is needed.

[vibhatha]

@vibhatha Well, can you make the PR description actually descriptive, instead of merely repeting the PR title? Thanks :-)

I will modify it 👍

[vibhatha]

@pitrou could you please check the updated description? Is it okay?

[ursabot]

Benchmark runs are scheduled for baseline = 32016b1 and contender = 791e5bd. 791e5bd is a master commit associated with this PR. Results will be available as each benchmark for each run completes.
Conbench compare runs links:
[Failed ⬇️0.0% ⬆️0.0%] ec2-t3-xlarge-us-east-2
[Failed ⬇️0.1% ⬆️0.0%] test-mac-arm
[Failed ⬇️0.32% ⬆️0.0%] ursa-i9-9960x
[Finished ⬇️0.25% ⬆️0.0%] ursa-thinkcentre-m75q
Buildkite builds:
[Failed] 791e5bd6 ec2-t3-xlarge-us-east-2
[Failed] 791e5bd6 test-mac-arm
[Failed] 791e5bd6 ursa-i9-9960x
[Finished] 791e5bd6 ursa-thinkcentre-m75q
[Failed] 32016b1a ec2-t3-xlarge-us-east-2
[Failed] 32016b1a test-mac-arm
[Failed] 32016b1a ursa-i9-9960x
[Finished] 32016b1a 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