chore: improve old value implementation performance

[trueadm]

This improves the signal runtime performance by opting for a linked list rather than a Map for storing old values. In theory a Map should be O(1) for lookups, but they come with overhead in terms when both setting a value and when clearing the Map down. Instead, using a linked list avoids this overhead except in the case where there might be many signal changes in the same update – in which case, maybe we should still opt to use a Map for those cases. Here are the benchmark results:

Main:

{
  benchmark: 'sbench_create_signals',
  time: '401.26',
  gc_time: '29.60'
}
{ benchmark: 'sbench_create_0to1', time: '8.17', gc_time: '0.00' }
{ benchmark: 'sbench_create_1to1', time: '29.06', gc_time: '0.59' }
{ benchmark: 'sbench_create_2to1', time: '27.08', gc_time: '0.52' }
{ benchmark: 'sbench_create_4to1', time: '25.51', gc_time: '0.61' }
{ benchmark: 'sbench_create_1000to1', time: '24.78', gc_time: '0.49' }
{ benchmark: 'sbench_create_1to2', time: '12.27', gc_time: '0.00' }
{ benchmark: 'sbench_create_1to4', time: '16.14', gc_time: '1.18' }
{ benchmark: 'sbench_create_1to8', time: '13.43', gc_time: '1.21' }
{ benchmark: 'sbench_create_1to1000', time: '4.89', gc_time: '0.00' }
{
  benchmark: 'kairo_avoidable_owned',
  time: '415.52',
  gc_time: '77.30'
}
{
  benchmark: 'kairo_avoidable_unowned',
  time: '507.39',
  gc_time: '73.81'
}
{ benchmark: 'kairo_broad_owned', time: '414.50', gc_time: '2.02' }
{ benchmark: 'kairo_broad_unowned', time: '413.50', gc_time: '2.16' }
{ benchmark: 'kairo_deep_owned', time: '181.87', gc_time: '1.93' }
{ benchmark: 'kairo_deep_unowned', time: '806.19', gc_time: '4.01' }
{ benchmark: 'kairo_diamond_owned', time: '340.28', gc_time: '34.45' }
{
  benchmark: 'kairo_diamond_unowned',
  time: '434.26',
  gc_time: '34.75'
}
{ benchmark: 'kairo_triangle_owned', time: '96.85', gc_time: '4.79' }
{
  benchmark: 'kairo_triangle_unowned',
  time: '198.79',
  gc_time: '4.57'
}
{ benchmark: 'kairo_mux_owned', time: '298.60', gc_time: '3.77' }
{ benchmark: 'kairo_mux_unowned', time: '450.16', gc_time: '3.95' }
{ benchmark: 'kairo_repeated_owned', time: '54.82', gc_time: '5.33' }
{ benchmark: 'kairo_repeated_unowned', time: '55.61', gc_time: '5.08' }
{ benchmark: 'kairo_unstable_owned', time: '88.33', gc_time: '5.46' }
{
  benchmark: 'kairo_unstable_unowned',
  time: '103.47',
  gc_time: '4.81'
}
{ benchmark: 'mol_bench_owned', time: '231.41', gc_time: '0.75' }
{ benchmark: 'mol_bench_unowned', time: '248.76', gc_time: '1.18' }

Finished reactivity benchmarks.

{ suite_time: '5902.90', suite_gc_time: '304.32' }

This PR:

{
  benchmark: 'sbench_create_signals',
  time: '296.43',
  gc_time: '78.94'
}
{ benchmark: 'sbench_create_0to1', time: '7.96', gc_time: '0.00' }
{ benchmark: 'sbench_create_1to1', time: '19.28', gc_time: '1.72' }
{ benchmark: 'sbench_create_2to1', time: '17.12', gc_time: '1.84' }
{ benchmark: 'sbench_create_4to1', time: '15.60', gc_time: '1.78' }
{ benchmark: 'sbench_create_1000to1', time: '14.50', gc_time: '1.63' }
{ benchmark: 'sbench_create_1to2', time: '9.62', gc_time: '0.53' }
{ benchmark: 'sbench_create_1to4', time: '19.26', gc_time: '6.70' }
{ benchmark: 'sbench_create_1to8', time: '14.69', gc_time: '3.57' }
{ benchmark: 'sbench_create_1to1000', time: '4.36', gc_time: '0.00' }
{
  benchmark: 'kairo_avoidable_owned',
  time: '359.36',
  gc_time: '67.77'
}
{
  benchmark: 'kairo_avoidable_unowned',
  time: '450.11',
  gc_time: '67.10'
}
{ benchmark: 'kairo_broad_owned', time: '416.18', gc_time: '1.68' }
{ benchmark: 'kairo_broad_unowned', time: '414.42', gc_time: '2.45' }
{ benchmark: 'kairo_deep_owned', time: '178.57', gc_time: '1.29' }
{ benchmark: 'kairo_deep_unowned', time: '823.22', gc_time: '3.19' }
{ benchmark: 'kairo_diamond_owned', time: '310.31', gc_time: '31.70' }
{
  benchmark: 'kairo_diamond_unowned',
  time: '406.96',
  gc_time: '31.66'
}
{ benchmark: 'kairo_triangle_owned', time: '93.90', gc_time: '5.69' }
{
  benchmark: 'kairo_triangle_unowned',
  time: '199.99',
  gc_time: '6.23'
}
{ benchmark: 'kairo_mux_owned', time: '299.27', gc_time: '3.63' }
{ benchmark: 'kairo_mux_unowned', time: '451.08', gc_time: '3.53' }
{ benchmark: 'kairo_repeated_owned', time: '51.61', gc_time: '4.41' }
{ benchmark: 'kairo_repeated_unowned', time: '52.58', gc_time: '4.54' }
{ benchmark: 'kairo_unstable_owned', time: '83.56', gc_time: '5.82' }
{
  benchmark: 'kairo_unstable_unowned',
  time: '101.41',
  gc_time: '5.96'
}
{ benchmark: 'mol_bench_owned', time: '232.01', gc_time: '0.80' }
{ benchmark: 'mol_bench_unowned', time: '249.05', gc_time: '1.24' }

Finished reactivity benchmarks.

{ suite_time: '5592.41', suite_gc_time: '345.40' }

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Latest commit: cc976d8

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