Add GHC 9.12.1 #2852

Job	Run time
cabal	2m 48s
cabal-doExactConfig	2m 44s
multi-target	5m 34s
nix-build	18m 43s
runghc	2m 1s
shellFor-hoogle	5m 12s
shellFor-multiple-package	4m 44s
shellFor-single-package	4m 47s
tests-benchmarks	7s
unit-tests	4s
build-extra-hackages	8s
docs	1m 34s
hix	3m 12s
hydra-ifdLevel-0-and-1	4m 13s
maintainer-scripts	9s
hydra-ifdLevel-2	7m 3s
plan-extra-hackages	9s
shellFor-not-depends	13s
check-materialization-concurrency	20s
check-path-support	8s
closure-size	3s
haskell-nix-roots-do-not-require-IFDs	10s
hydra-ifdLevel-3	30m 10s
hix-cabal	13s
hydra-without-remote-builders-ghc8107	2m 37s
nix-tools	12s
hydra-without-remote-builders-ghc9101	1m 58s
update-docs	5s
	1h 39m 21s

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