Update tests to haskell-language-server 2.7 #2044

Job	Run time
cabal	12s
nix-build	1m 40s
runghc	11s
unit-tests	17s
cabal-doExactConfig	15s
multi-target	21s
shellFor-hoogle	13s
shellFor-multiple-package	17s
shellFor-not-depends	15s
shellFor-single-package	15s
tests-benchmarks	10s
build-extra-hackages	8s
docs	38s
hix	1m 22s
hydra-ifdLevel-0-and-1	16s
hydra-ifdLevel-2	14s
hydra-ifdLevel-3-and-ghc-8-10	7s
hydra-ifdLevel-3-and-ghc-9-2	8s
hydra-ifdLevel-3-and-not-ghc-8-10-or-9-2	13s
maintainer-scripts	12s
plan-extra-hackages	9s
check-materialization-concurrency	20s
check-path-support	9s
closure-size	8s
haskell-nix-roots-do-not-require-IFDs	9s
hix-cabal	32s
hydra-without-remote-builders	37s
nix-tools	18s
update-docs	6s
	9m 52s

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