Stacked on #60502 and targets it — #60502 must land first (its
orchestrator fix is what lets this `tooling/lints/`-touching PR go green
rather than tripping the `rdeps(lints)` nextest filter). Re-creates the
symlinks from #60504, which was accidentally merged into #60502's branch
and reverted.

Follow-up to #60468, which added a `LICENSE-APACHE` symlink to the
`tooling/lints` crate but not to the `test_fixture` sub-crates. Those
five sub-crates each carry a `Cargo.toml`, so `script/check-licenses`
requires a `LICENSE-GPL`/`LICENSE-APACHE` symlink in each, and
`check_licenses` fails on any PR that changes `Cargo.lock`. This adds
`LICENSE-APACHE` symlinks to the five fixture crates, matching #60468;
`script/check-licenses` passes locally afterward.

Release Notes:

- N/A