Run tests/rustdoc-json/attrs/target_features on all hosts.

[aDotInTheVoid]

Makes it more convenient to test rustdoc on non x86_64. I mainly care about the aarch64 dev-desktops.

This works because rustdoc uses all target features, not just that of the target.

[rustbot]

r? @Mark-Simulacrum

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[rustbot]

These commits modify tests/rustdoc-json.
rustdoc-json is a public (but unstable) interface.

Please ensure that if you've changed the output:

• It's intentional.
• The FORMAT_VERSION in src/librustdoc-json-types is bumped if necessary.

cc @aDotInTheVoid, @obi1kenobi

[aDotInTheVoid]

I don't think PR CI will test this, but it does work:

gh-aDotInTheVoid@dev-desktop-eu-1:~/rust3$ uname -m
aarch64
gh-aDotInTheVoid@dev-desktop-eu-1:~/rust3$ ./x test ./tests/rustdoc-json/attrs/target_feature.rs --force-rerun
Building bootstrap
    Finished `dev` profile [unoptimized] target(s) in 0.06s
/home/gh-aDotInTheVoid/rust3/build/aarch64-unknown-linux-gnu/ci-llvm/bin/llvm-strip does not exist; skipping copy
Creating a sysroot for stage2 compiler (use `rustup toolchain link 'name' build/host/stage2`)
Building stage0 tool compiletest (aarch64-unknown-linux-gnu)
    Finished `release` profile [optimized] target(s) in 0.20s
Building stage0 tool jsondocck (aarch64-unknown-linux-gnu)
    Finished `release` profile [optimized] target(s) in 0.17s
Building stage0 tool jsondoclint (aarch64-unknown-linux-gnu)
    Finished `release` profile [optimized] target(s) in 0.17s
Testing stage2 compiletest suite=rustdoc-json mode=rustdoc-json (aarch64-unknown-linux-gnu)

running 1 tests
.

test result: ok. 1 passed; 0 failed; 0 ignored; 0 measured; 170 filtered out; finished in 426.34ms

Build completed successfully in 0:00:02