Retire `[@@must_erase_for_extraction]` #637

Job	Run time
nix / fstar-nix	18m 13s
opam / build (5.3)	20m 45s
opam / build (4.14.2)	17m 8s
build / build	18m 40s
tests / test-local	16m 8s
tests / ocaml-smoke (fstar-src.tar.gz, ubuntu-24.04)	7m 21s
tests / binary-smoke	17s
tests / check-stage3	6m 5s
tests / ocaml-smoke (fstar-src.tar.gz, ubuntu-latest)	7m 32s
tests / perf-canaries	13s
ciok	0s
	1h 52m 22s

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