Ensure we do incremental builds in Cargo

[delan]

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[delan]

Interesting behaviour in servo-ubuntu2204. While building the image:

• export CARGO_LOG=cargo::core::compiler::fingerprint=info
• ./mach build --use-crown --locked --release --features layout_2013 -v 2>&1 | tee /init/build0.log
• git status
• ./mach build --use-crown --locked --release --features layout_2013 -v 2>&1 | tee /init/build1.log

While booting up a runner:

• export CARGO_LOG=cargo::core::compiler::fingerprint=info
• ./mach build --use-crown --locked --release --features layout_2013 -v 2>&1 | tee /init/build2.log

Notably in build1.log:

   0.400614548s  INFO prepare_target{force=false package_id=servoshell v0.0.1 (/a/servo/servo/ports/servoshell) target="servoshell"}: cargo::core::compiler::fingerprint: stale: changed "/a/servo/servo/components/script/dom/bindings/codegen"
   0.400638833s  INFO prepare_target{force=false package_id=servoshell v0.0.1 (/a/servo/servo/ports/servoshell) target="servoshell"}: cargo::core::compiler::fingerprint:           (vs) "/a/servo/servo/target/release/build/script-eec0d962ff2119b5/output"
   0.400641628s  INFO prepare_target{force=false package_id=servoshell v0.0.1 (/a/servo/servo/ports/servoshell) target="servoshell"}: cargo::core::compiler::fingerprint:                FileTime { seconds: 1737690444, nanos: 43541920 } < FileTime { seconds: 1737690444, nanos: 187541324 }
   0.404951772s  INFO prepare_target{force=false package_id=servoshell v0.0.1 (/a/servo/servo/ports/servoshell) target="servoshell"}: cargo::core::compiler::fingerprint: fingerprint dirty for servoshell v0.0.1 (/a/servo/servo/ports/servoshell)/Build/TargetInner { benched: false, ..: lib_target("servoshell", ["lib"], "/a/servo/servo/ports/servoshell/lib.rs", Edition2021) }
   0.404970838s  INFO prepare_target{force=false package_id=servoshell v0.0.1 (/a/servo/servo/ports/servoshell) target="servoshell"}: cargo::core::compiler::fingerprint:     dirty: FsStatusOutdated(StaleDepFingerprint { name: "servo" })
   0.409901212s  INFO prepare_target{force=false package_id=libservo v0.0.1 (/a/servo/servo/components/servo) target="servo"}: cargo::core::compiler::fingerprint: fingerprint dirty for libservo v0.0.1 (/a/servo/servo/components/servo)/Build/TargetInner { ..: lib_target("servo", ["rlib"], "/a/servo/servo/components/servo/lib.rs", Edition2021) }
   0.409915539s  INFO prepare_target{force=false package_id=libservo v0.0.1 (/a/servo/servo/components/servo) target="servo"}: cargo::core::compiler::fingerprint:     dirty: FsStatusOutdated(StaleDepFingerprint { name: "layout_thread_2013" })
   0.420420283s  INFO prepare_target{force=false package_id=layout_thread_2013 v0.0.1 (/a/servo/servo/components/layout_thread) target="layout_thread_2013"}: cargo::core::compiler::fingerprint: fingerprint dirty for layout_thread_2013 v0.0.1 (/a/servo/servo/components/layout_thread)/Build/TargetInner { ..: lib_target("layout_thread_2013", ["lib"], "/a/servo/servo/components/layout_thread/lib.rs", Edition2021) }
   0.420435913s  INFO prepare_target{force=false package_id=layout_thread_2013 v0.0.1 (/a/servo/servo/components/layout_thread) target="layout_thread_2013"}: cargo::core::compiler::fingerprint:     dirty: FsStatusOutdated(StaleDepFingerprint { name: "script" })
   0.420715034s  INFO prepare_target{force=false package_id=script v0.0.1 (/a/servo/servo/components/script) target="script"}: cargo::core::compiler::fingerprint: fingerprint dirty for script v0.0.1 (/a/servo/servo/components/script)/Build/TargetInner { ..: lib_target("script", ["lib"], "/a/servo/servo/components/script/lib.rs", Edition2021) }
   0.420766360s  INFO prepare_target{force=false package_id=script v0.0.1 (/a/servo/servo/components/script) target="script"}: cargo::core::compiler::fingerprint:     dirty: FsStatusOutdated(StaleDepFingerprint { name: "build_script_build" })
   0.427173847s  INFO prepare_target{force=false package_id=script v0.0.1 (/a/servo/servo/components/script) target="build-script-build"}: cargo::core::compiler::fingerprint: fingerprint dirty for script v0.0.1 (/a/servo/servo/components/script)/RunCustomBuild/TargetInner { ..: custom_build_target("build-script-build", "/a/servo/servo/components/script/build.rs", Edition2021) }
   0.427183416s  INFO prepare_target{force=false package_id=script v0.0.1 (/a/servo/servo/components/script) target="build-script-build"}: cargo::core::compiler::fingerprint:     dirty: FsStatusOutdated(StaleItem(ChangedFile { reference: "/a/servo/servo/target/release/build/script-eec0d962ff2119b5/output", reference_mtime: FileTime { seconds: 1737690444, nanos: 43541920 }, stale: "/a/servo/servo/components/script/dom/bindings/codegen", stale_mtime: FileTime { seconds: 1737690444, nanos: 187541324 } }))
   0.427730360s  INFO prepare_target{force=false package_id=layout_thread_2020 v0.0.1 (/a/servo/servo/components/layout_thread_2020) target="layout_thread_2020"}: cargo::core::compiler::fingerprint: fingerprint dirty for layout_thread_2020 v0.0.1 (/a/servo/servo/components/layout_thread_2020)/Build/TargetInner { ..: lib_target("layout_thread_2020", ["lib"], "/a/servo/servo/components/layout_thread_2020/lib.rs", Edition2021) }
   0.427742523s  INFO prepare_target{force=false package_id=layout_thread_2020 v0.0.1 (/a/servo/servo/components/layout_thread_2020) target="layout_thread_2020"}: cargo::core::compiler::fingerprint:     dirty: FsStatusOutdated(StaleDepFingerprint { name: "script" })
   0.431510231s  INFO prepare_target{force=false package_id=servoshell v0.0.1 (/a/servo/servo/ports/servoshell) target="servo"}: cargo::core::compiler::fingerprint: fingerprint dirty for servoshell v0.0.1 (/a/servo/servo/ports/servoshell)/Build/TargetInner { name: "servo", benched: false, doc: true, ..: with_path("/a/servo/servo/ports/servoshell/main.rs", Edition2021) }
   0.431591353s  INFO prepare_target{force=false package_id=servoshell v0.0.1 (/a/servo/servo/ports/servoshell) target="servo"}: cargo::core::compiler::fingerprint:     dirty: FsStatusOutdated(StaleDepFingerprint { name: "servo" })