Clean up IdDict use with macro

[MilesCranmer]

This should greatly speed up the simplify_tree and combine_operators functions, as before this change they made the assumption that a child node might have multiple parent nodes.

TODO:

• [x] Add benchmark for these functions (with and without topology preservation)

[coveralls]

Pull Request Test Coverage Report for Build 4775403269

• 125 of 127 (98.43%) changed or added relevant lines in 3 files are covered.
• 1 unchanged line in 1 file lost coverage.
• Overall coverage decreased (-0.06%) to 89.449%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
src/SimplifyEquation.jl	80	82	97.56%
<!--	Total:	125	127	98.43%	-->

Files with Coverage Reduction	New Missed Lines	%
src/EvaluateEquation.jl	1	99.62%
<!--	Total:	1		-->

Totals
Change from base Build 4774460028:	-0.06%
Covered Lines:	958
Relevant Lines:	1071

---

💛 - Coveralls

[MilesCranmer]

@AlCap23 would you be up for a quick review of this?

[github-actions[bot]]

Benchmark Results

	master	ea3e91c921c553...	t[master]/t[ea3e91c921c553...]
eval/ComplexF32/evaluation	10.4 ± 0.69 ms	10.2 ± 0.58 ms	1.03
eval/ComplexF64/evaluation	12.5 ± 0.76 ms	12.5 ± 0.82 ms	0.997
eval/Float32/derivative	15.5 ± 0.82 ms	15.7 ± 0.93 ms	0.983
eval/Float32/derivative_turbo	18.4 ± 0.69 ms	18.5 ± 0.67 ms	0.997
eval/Float32/evaluation	3.56 ± 0.28 ms	3.55 ± 0.28 ms	1
eval/Float32/evaluation_turbo	0.884 ± 0.035 ms	0.869 ± 0.034 ms	1.02
eval/Float64/derivative	20 ± 2.4 ms	19.3 ± 2.5 ms	1.04
eval/Float64/derivative_turbo	23 ± 2.4 ms	22.9 ± 2.5 ms	1
eval/Float64/evaluation	4.11 ± 0.33 ms	4.15 ± 0.31 ms	0.992
eval/Float64/evaluation_turbo	1.31 ± 0.049 ms	1.32 ± 0.055 ms	0.991
time_to_load	12.4 ± 0.017 s	12.3 ± 0.019 s	1
utils/combine_operators/break_sharing	0.056 ± 0.0028 ms	0.0561 ± 0.003 ms	0.998
utils/convert/break_sharing	0.0518 ± 0.0077 ms	0.0518 ± 0.0071 ms	1
utils/convert/preserve_sharing	0.24 ± 0.011 ms	0.238 ± 0.0093 ms	1.01
utils/copy/break_sharing	0.0484 ± 0.0086 ms	0.0481 ± 0.0071 ms	1.01
utils/copy/preserve_sharing	0.24 ± 0.013 ms	0.235 ± 0.009 ms	1.02
utils/simplify_tree/break_sharing	0.163 ± 0.017 ms	0.163 ± 0.016 ms	1

Benchmark Plots

A plot of the benchmark results have been uploaded as an artifact to the workflow run for this PR. Go to "Actions"->"Benchmark a pull request"->[the most recent run]->"Artifacts" (at the bottom).