refactor: remove pointless real_role alias #29725

Job	Run time
Build microbenchmarks	2m 29s
Coq 8.16.1	7m 5s
Create local opam switch (macos-latest, 5)	6m 51s
Build (macos-latest, 5.1.x)	13m 56s
Create local opam switch (macos-latest, 4.14)	5m 37s
Build (ubuntu-latest, 5.1.x)	8m 42s
Documentation	1m 0s
Create local opam switch (ubuntu-latest, 5)	4m 59s
Build (ocaml-variants.5.4.0+trunk, ubuntu-latest, true)	1m 35s
Format	1m 7s
Create local opam switch (ubuntu-latest, 4.14)	4m 51s
Build (4.14.x, ubuntu-latest, true)	1m 28s
Build (4.14.x, macos-latest, true)	2m 55s
Build monorepo benchmark docker image	3m 45s
Nix (macos-latest)	1m 54s
Build (5.1.x, macos-13, true)	3m 42s
Wasm_of_ocaml	11m 26s
Nix (ubuntu-latest)	54s
Build (ocaml-base-compiler.4.14.2,system-msvc, windows-latest)	15m 42s
Build (ocaml-base-compiler.5.1.1,system-mingw, windows-latest)	8m 22s
Build (4.08.x, ubuntu-latest, true)	1m 26s
Build (4.04.x, ubuntu-latest, true, true)	4m 33s
Build (4.02.x, ubuntu-latest, true)	3m 54s
	1h 58m 13s

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