- Mark the hook that we're exporting for the threading library to call
to clean up per-thread malloc state as 'used'. It was changed to
`inline` to allow duplicate copies of it to be merged but this also
means that it isn't emitted at all in compilation units that don't
use it (and it isn't used internally at all).
- Fix the `__je_bootstrap_*` functions, which are used to bootstrap TLS
allocation, for the changes to `ScopedAllocator`.
The `__je_bootstrap*` functions weren't being built in CI. They now are
for non-PIE targets with a smoke test.