Replace default sorter in Enum.sort_by/3 with :asc (#11856)
Replace default sorter in Enum.sort_by/3 with :asc (#11856)

Enum.sort_by/3 works faster with :asc than with &<=/2.
The previous default could go from 1.52x to 2.21x slower; same goes for memory usage.

The benchmark:
https://github.com/eksperimental/benchmark/blob/enum_sort_by/benchmarks/enum_sort_by_default_sorter.exs

The benchmark results:
https://gist.github.com/eksperimental/f16e6df01e193cf075157a932bcd573c

Closes: https://github.com/elixir-lang/elixir/issues/11808

elixir-lang/elixir,michalmuskala/elixir