add ilike comparitor

[jwdeitch]

Which issue does this PR close?

Closes #873.

Are there any user-facing changes?

adding ilike comparison operator to bring more pgSQL compatibility ultimately into datafusion

[alamb]

Thanks for the contribution @jwdeitch ! I plan to review this more carefully this weekend, but what I have seen so far looks very nice

[codecov-commenter]

Codecov Report

Merging #874 (baaad3a) into master (05eb63f) will decrease coverage by 0.12%.
The diff coverage is 85.79%.

❗ Current head baaad3a differs from pull request most recent head bf1c495. Consider uploading reports for the commit bf1c495 to get more accurate results

@@            Coverage Diff             @@
##           master     #874      +/-   ##
==========================================
- Coverage   82.45%   82.33%   -0.13%     
==========================================
  Files         168      168              
  Lines       48175    48490     +315     
==========================================
+ Hits        39723    39923     +200     
- Misses       8452     8567     +115     

Impacted Files	Coverage Δ
arrow-flight/src/arrow.flight.protocol.rs	0.00% <ø> (ø)
arrow/src/array/cast.rs	85.71% <ø> (ø)
arrow/src/array/transform/mod.rs	85.33% <ø> (-0.18%)	⬇️
arrow/src/csv/writer.rs	82.05% <ø> (-0.37%)	⬇️
arrow/src/error.rs	13.33% <0.00%> (ø)
...ng/src/flight_server_scenarios/auth_basic_proto.rs	0.00% <0.00%> (ø)
parquet/src/data_type.rs	76.84% <ø> (-0.48%)	⬇️
parquet/src/schema/parser.rs	85.11% <0.00%> (-1.26%)	⬇️
parquet/src/util/bit_packing.rs	99.96% <ø> (ø)
parquet/src/util/bit_util.rs	93.19% <ø> (+0.01%)	⬆️
... and 109 more

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[alamb]

Thank you @jwdeitch I think this looks great (including the tests).

We are sorting out the MIRI failures now that seem to be happening on master in CI -- #879 -- and once that is sorted we can merge this in

If you have the time / inclination, I think it would be really neat to reduce the copy/paste in the ilike, like, nlike,` etc kernels. I left a comment to this effect above

[alamb]

@jwdeitch bf1c495 is a thing of beauty. Thank you so much for sticking with it. ❤️

I kicked off CI and plan to merge this PR when it passes

[alamb]

Thanks again @jwdeitch 👍