Implement Eq trait for Expr and nested types

[jdye64]

Rationale for this change

Expr is currently not compatible with the HashSet container because it does not implement to std::cmp::Eq trait. This PR implements that trait for Expr and any nested components

[codecov-commenter]

Codecov Report

Merging #3381 (705522f) into master (c89b10f) will decrease coverage by 0.00%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #3381      +/-   ##
==========================================
- Coverage   85.58%   85.57%   -0.01%     
==========================================
  Files         296      296              
  Lines       54179    54179              
==========================================
- Hits        46367    46366       -1     
- Misses       7812     7813       +1     

Impacted Files	Coverage Δ
datafusion/expr/src/expr.rs	76.08% <ø> (ø)
datafusion/expr/src/logical_plan/plan.rs	77.61% <ø> (+0.33%)	⬆️
datafusion/expr/src/udaf.rs	37.50% <ø> (-12.50%)	⬇️
datafusion/expr/src/udf.rs	60.00% <ø> (ø)
datafusion/core/src/physical_plan/metrics/value.rs	86.93% <0.00%> (-0.51%)	⬇️

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[alamb]

I think this looks good to me. Thanks @jdye64

[alamb]

well I suppose Eq is satisfied given that PartialEq always returns false the requirements

https://doc.rust-lang.org/std/cmp/trait.Eq.html

are satisfied in a strange sort of way

[alamb]

👍

[ursabot]

Benchmark runs are scheduled for baseline = 43e2d91 and contender = e6d1364. e6d1364 is a master commit associated with this PR. Results will be available as each benchmark for each run completes.
Conbench compare runs links:
[Skipped ⚠️ Benchmarking of arrow-datafusion-commits is not supported on ec2-t3-xlarge-us-east-2] ec2-t3-xlarge-us-east-2
[Skipped ⚠️ Benchmarking of arrow-datafusion-commits is not supported on test-mac-arm] test-mac-arm
[Skipped ⚠️ Benchmarking of arrow-datafusion-commits is not supported on ursa-i9-9960x] ursa-i9-9960x
[Skipped ⚠️ Benchmarking of arrow-datafusion-commits is not supported on ursa-thinkcentre-m75q] ursa-thinkcentre-m75q
Buildkite builds:
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