better ordering of terms

[shashi]

julia> expand((x+y-1)^4)
1 - 4x - 4y + 6(x^2) + 12x*y + 6(y^2) - 4(x^3) - 12(x^2)*y - 12x*(y^2) - 4(y^3) + x^4 + 4(x^3)*y + 6(x^2)*(y^2) + 4x*(y^3) + y^4

arguments no more uses <ₑ; <ₑ does still maintain a total order, is tested, and used for simplification in non-canonical cases.

[github-actions]

Benchmark Results

	master	f0cfce0...	t[master]/t[f0cfce0...]
overhead/acrule/a+2	1.08 ± 0.24 μs	1.08 ± 0.25 μs	1
overhead/acrule/a+2+b	1.07 ± 0.24 μs	1.07 ± 0.25 μs	1
overhead/acrule/a+b	0.358 ± 0.0073 μs	0.358 ± 0.0087 μs	1
overhead/acrule/noop:Int	26.4 ± 0.9 ns	26.2 ± 0.7 ns	1.01
overhead/acrule/noop:Sym	0.0539 ± 0.0083 μs	0.0557 ± 0.0076 μs	0.969
overhead/rule/noop:Int	0.0472 ± 0.0022 μs	0.0453 ± 0.0022 μs	1.04
overhead/rule/noop:Sym	0.0589 ± 0.003 μs	0.0596 ± 0.003 μs	0.987
overhead/rule/noop:Term	0.0592 ± 0.0029 μs	0.0594 ± 0.0029 μs	0.997
overhead/ruleset/noop:Int	0.167 ± 0.0032 μs	0.167 ± 0.0024 μs	0.999
overhead/ruleset/noop:Sym	0.2 ± 0.0067 μs	0.203 ± 0.007 μs	0.984
overhead/ruleset/noop:Term	4.41 ± 0.29 μs	4.41 ± 0.33 μs	1
overhead/simplify/noop:Int	0.217 ± 0.0088 μs	0.221 ± 0.0092 μs	0.98
overhead/simplify/noop:Sym	0.231 ± 0.0053 μs	0.247 ± 0.0055 μs	0.935
overhead/simplify/noop:Term	0.0468 ± 0.0037 ms	0.0462 ± 0.0036 ms	1.01
overhead/simplify/randterm (+, *):serial	0.13 ± 0.0021 s	0.167 ± 0.0015 s	0.781
overhead/simplify/randterm (+, *):thread	0.0789 ± 0.016 s	0.114 ± 0.016 s	0.693
overhead/simplify/randterm (/, *):serial	0.288 ± 0.01 ms	0.285 ± 0.0094 ms	1.01
overhead/simplify/randterm (/, *):thread	0.334 ± 0.011 ms	0.329 ± 0.0098 ms	1.01
overhead/substitute/a	0.0738 ± 0.0021 ms	0.0723 ± 0.0018 ms	1.02
overhead/substitute/a,b	0.0634 ± 0.0021 ms	0.0629 ± 0.0019 ms	1.01
overhead/substitute/a,b,c	21.2 ± 0.7 μs	21.6 ± 0.7 μs	0.981
polyform/easy_iszero	0.0387 ± 0.0032 ms	0.0388 ± 0.0034 ms	0.997
polyform/isone	3.1 ± 0.1 ns	3.1 ± 0.1 ns	1
polyform/iszero	1.63 ± 0.036 ms	2.43 ± 0.032 ms	0.67
polyform/simplify_fractions	2.29 ± 0.04 ms	3.26 ± 0.037 ms	0.703
time_to_load	5.55 ± 0.037 s	5.44 ± 0.015 s	1.02

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).