refactor(pkg): remove some unused stuff (#11459) #29956

Job	Run time
Build microbenchmarks	2m 31s
Coq 8.16.1	7m 7s
Create local opam switch (macos-latest, 5)	1m 3s
Build (macos-latest, 5.1.x)	47s
Create local opam switch (macos-latest, 4.14)	46s
Build (ubuntu-latest, 5.1.x)	8m 12s
Create local opam switch (ubuntu-latest, 5)	1m 2s
Documentation	2m 59s
Build (ocaml-variants.5.4.0+trunk, ubuntu-latest, true)	2m 16s
Create local opam switch (ubuntu-latest, 4.14)	49s
Format	1m 8s
Build (4.14.x, ubuntu-latest, true)	1m 25s
Build (4.14.x, macos-latest, true)	47s
Build monorepo benchmark docker image	3m 55s
Build (5.1.x, macos-13, true)	3m 30s
Nix (macos-latest)	1m 57s
Wasm_of_ocaml	10m 31s
Build (ocaml-base-compiler.4.14.2,system-msvc, windows-latest)	8m 13s
Nix (ubuntu-latest)	51s
Build (ocaml-base-compiler.5.1.1,system-mingw, windows-latest)	7m 32s
Build (4.08.x, ubuntu-latest, true)	1m 26s
	1h 8m 47s

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