… consts

- Use `cargo metadata` to determine whether a crate has a library
  package or not
- Collect metadata for all workspaces, not just the root workspace and
  cargo
- Don't pass `--lib` for crates without a library
- Use `run_cargo_test` for rust-installer
- Don't build documentation in `lint-docs` if `--no-doc` is passed

…jackh726

Suggest using integration tests for test crate using own proc-macro

cc rust-lang#110247

…unsound-issues, r=jackh726

Add `known-bug` tests for 11 unsound issues

r? `@jackh726`

Should tests for other issues be in separate PRs?  Thanks.

Edit: Partially addresses rust-lang#105107.  This PR adds `known-bug` tests for 11 unsound issues:
- rust-lang#25860
- rust-lang#49206
- rust-lang#57893
- rust-lang#84366
- rust-lang#84533
- rust-lang#84591
- rust-lang#85099
- rust-lang#98117
- rust-lang#100041
- rust-lang#100051
- rust-lang#104005

…levant_impl, r=b-naber

Remove `find_map_relevant_impl`

Fixes rust-lang#108895

bootstrap: Unify test argument handling

Fixes rust-lang#104198. Does *not* help with rust-lang#80124 because I couldn't figure out a reasonable way to omit `--lib` only for `panic_abort` and not other `std` dependencies.

- Remove unnecessary `test_kind` field and `TestKind` struct. These are just subsets of the existing `builder.kind` / `Kind` struct.
- Add a new `run_cargo_test` function which handles passing arguments to cargo based on `builder.config`
- Switch all Steps in `mod test` to `run_cargo_test` where possible
- Combine several steps into one `CrateBootstrap` step. These tests all do the same thing, just with different crate names.
- Fix `x test --no-doc`. This is much simpler after the refactors mentioned earlier, but I'm happy to split it into a separate PR if desired. Before, this would panic a lot because steps forgot to pass `--lib`.

…=jackh726

Add some tests around (lack of) object safety of associated types and consts

See https://rust-lang.zulipchat.com/#narrow/stream/144729-t-types/topic/.60where.20Self.3ASized.60.20on.20assoc.20types/near/351260928 for some discussion around why this isn't allowed.

We didn't have any tests for these, so I decided to add them now, even if we don't end up doing anything about it.