compiletest: Report filtered and --skip-ed tests in metrics

[jyn514]

Ferrocene depends on these metrics for our certification. For various reasons our CI invokes bootstrap with --skip flags, so we want to report ignored tests even if they're ignored manually with --skip.

To make sure this doesn't regress, add an integration test suite for compiletest itself. This can't fit into the existing compiletest-self-test suite because it's testing the interface between bootstrap and compiletest, not just whether the tests pass or fail. Hopefully this will come in handy for more things in the future.

---

Changes in this PR:

• Move deserialization of compiletest JSON from bootstrap to build_helper. Derive Debug on all its types.
• Add std to the sysroot before running compiletest self-tests, so that it can run integration tests and not just unit tests.
• Add a new FilteredOut metric kind. Handle it appropriately (by not doing anything) in progress reporting, but save it to the metrics.json file.

[rustbot]

These commits modify the Cargo.lock file. Unintentional changes to Cargo.lock can be introduced when switching branches and rebasing PRs.

If this was unintentional then you should revert the changes before this PR is merged.
Otherwise, you can ignore this comment.

Some changes occurred in src/tools/compiletest

cc @jieyouxu

[rustbot]

r? @Mark-Simulacrum

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The reviewer was selected based on:

• Owners of files modified in this PR: @jieyouxu, @oli-obk, @wesleywiser, bootstrap
• @jieyouxu, @oli-obk, @wesleywiser, bootstrap expanded to 8 candidates
• Random selection from Mark-Simulacrum, clubby789, jieyouxu, wesleywiser

[rust-log-analyzer]

The job aarch64-gnu-llvm-21-2 failed! Check out the build log: (web) (plain enhanced) (plain)

Click to see the possible cause of the failure (guessed by this bot)

##[endgroup]
Executing "/scripts/stage_2_test_set2.sh"
+ /scripts/stage_2_test_set2.sh
+ '[' 1 == 1 ']'
+ echo 'PR_CI_JOB set; skipping tidy'
+ SKIP_TIDY='--skip tidy'
+ ../x.py --stage 2 test --skip tidy --skip tests --skip coverage-map --skip coverage-run --skip library --skip tidyselftest
PR_CI_JOB set; skipping tidy
##[group]Building bootstrap
    Finished `dev` profile [unoptimized] target(s) in 0.04s
##[endgroup]
---
────────────────────────────────────────────────────────────────────────────────
-old snapshot
+new results
────────────┬───────────────────────────────────────────────────────────────────
    0     0 │ [build] llvm <host>
    1     1 │ [build] rustc 0 <host> -> rustc 1 <host>
    2       │-[build] rustdoc 0 <host>
          2 │+[build] rustdoc 0 <host>
          3 │+[build] rustc 1 <host> -> std 1 <host>
────────────┴───────────────────────────────────────────────────────────────────
Stopped on the first failure. Run `cargo insta test` to run all snapshots.

thread 'core::builder::tests::snapshot::test_compiletest_self_test' (11474) panicked at /cargo/registry/src/index.crates.io-1949cf8c6b5b557f/insta-1.43.1/src/runtime.rs:679:13:
snapshot assertion for 'compiletest_self_test' failed in line 2161
stack backtrace:
   0: __rustc::rust_begin_unwind
             at /rustc/ef0fb8a2563200e322fa4419f09f65a63742038c/library/std/src/panicking.rs:689:5
   1: core::panicking::panic_fmt
             at /rustc/ef0fb8a2563200e322fa4419f09f65a63742038c/library/core/src/panicking.rs:80:14
   2: <insta::runtime::SnapshotAssertionContext>::finalize
             at /cargo/registry/src/index.crates.io-1949cf8c6b5b557f/insta-1.43.1/src/runtime.rs:679:13
   3: insta::runtime::assert_snapshot
             at /cargo/registry/src/index.crates.io-1949cf8c6b5b557f/insta-1.43.1/src/runtime.rs:848:13
   4: bootstrap::core::builder::tests::snapshot::test_compiletest_self_test
             at ./src/core/builder/tests.rs:2161:9
   5: bootstrap::core::builder::tests::snapshot::test_compiletest_self_test::{closure#0}
             at ./src/core/builder/tests.rs:2158:36
   6: <bootstrap::core::builder::tests::snapshot::test_compiletest_self_test::{closure#0} as core::ops::function::FnOnce<()>>::call_once