fix: max of 6 expressions bug

[MilesCranmer]

Fixes MilesCranmer/PySR#829 by @CleverCompiler-oss

[github-actions]

Benchmark Results

	master	69abc94...	master/69abc941fc3a35...
search/multithreading	17.6 ± 0.73 s	17.1 ± 0.6 s	1.03
search/serial	29.4 ± 0.43 s	29.1 ± 0.2 s	1.01
utils/best_of_sample	1.65 ± 0.55 μs	1.73 ± 1.1 μs	0.954
utils/check_constraints_x10	12.3 ± 3.4 μs	12.4 ± 3.4 μs	0.995
utils/compute_complexity_x10/Float64	2.16 ± 0.21 μs	2.14 ± 0.23 μs	1.01
utils/compute_complexity_x10/Int64	2.14 ± 0.19 μs	2.11 ± 0.21 μs	1.01
utils/compute_complexity_x10/nothing	1.48 ± 0.2 μs	1.52 ± 0.18 μs	0.973
utils/insert_random_op_x10	5.91 ± 1.8 μs	5.85 ± 2.1 μs	1.01
utils/next_generation_x100	0.406 ± 0.083 ms	0.36 ± 0.099 ms	1.13
utils/optimize_constants_x10	0.0344 ± 0.0082 s	0.0353 ± 0.0085 s	0.973
utils/randomly_rotate_tree_x10	5.4 ± 0.73 μs	5.47 ± 0.7 μs	0.987
time_to_load	1.96 ± 0.013 s	1.97 ± 0.011 s	0.997

Benchmark Plots

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Go to "Actions"->"Benchmark a pull request"->[the most recent run]->"Artifacts" (at the bottom).

[coveralls]

Pull Request Test Coverage Report for Build 13317475983

Warning: This coverage report may be inaccurate.

This pull request's base commit is no longer the HEAD commit of its target branch. This means it includes changes from outside the original pull request, including, potentially, unrelated coverage changes.

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Details

• 1 of 1 (100.0%) changed or added relevant line in 1 file are covered.
• 1 unchanged line in 1 file lost coverage.
• Overall coverage decreased (-0.03%) to 95.101%

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Files with Coverage Reduction	New Missed Lines	%
src/SymbolicRegression.jl	1	98.3%

Totals
Change from base Build 13230147881:	-0.03%
Covered Lines:	3397
Relevant Lines:	3572

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💛 - Coveralls