Add Nix support to language tests #64

Job	Run time
rustfmt	14s
lint-build	2m 16s
test-flake (x86_64-unknown-linux-gnu)	10m 51s
test (stable, x86_64-unknown-linux-gnu)	4m 58s
test-wasm	1m 13s
test-flake (x86_64-unknown-linux-musl)	10m 42s
test (stable, x86_64-unknown-linux-musl)	6m 3s
test-flake (aarch64-unknown-linux-gnu)	10m 50s
test (stable, aarch64-unknown-linux-gnu)	4m 0s
test-flake (aarch64-unknown-linux-musl)	10m 52s
test (stable, aarch64-unknown-linux-musl)	4m 5s
test-flake (x86_64-apple-darwin)	10m 40s
test (stable, x86_64-apple-darwin)	9m 11s
test-flake (aarch64-apple-darwin, macos-14)	7m 16s
test (stable, x86_64-pc-windows-msvc)	5m 10s
test (stable, aarch64-apple-darwin, macos-latest, false, true, true)	4m 27s
test-projects	1m 52s
	1h 44m 40s

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