Add support for WASM backend #3317

Job	Run time
cabal	6h 0m 17s
runghc	6h 0m 17s
unit-tests	9s
nix-build	1m 30s
cabal-doExactConfig	6h 0m 17s
multi-target	12s
hydra-without-remote-builders-ghc9102	1m 59s
docs	6h 0m 17s
hydra-ifdLevel-0-and-1	3m 40s
check-path-support	6h 0m 17s
plan-extra-hackages	10s
hydra-without-remote-builders-ghc967	1m 28s
hydra-ifdLevel-3	30m 17s
shellFor-hoogle	6h 0m 16s
tests-benchmarks	6h 0m 18s
shellFor-multiple-package	1s
update-docs	1s
shellFor-single-package	1d 0h 0m 0s
shellFor-not-depends	1s
hix	1s
build-extra-hackages	1s
closure-size	1d 0h 0m 0s
hydra-ifdLevel-2	1s
maintainer-scripts	1s
check-materialization-concurrency	1s
check-nix-tools	1s
haskell-nix-roots-do-not-require-IFDs	1s
hix-cabal	1s
	3d 18h 41m 35s

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