When building with the `--shared` option, most functionality is kept in
`libruby.so`. Therefore also run annocheck for `libruby.so`.

Use `ARG IN_DIR` to propagate multiple files into the container instead of
`ARG FILES` in the `Dockerfile-copy`. Because the `COPY` syntax in Dockerfile
doesn't support copying the multiple files.
https://stackoverflow.com/questions/61599384/specify-multiple-files-in-arg-to-copy-in-dockerfile

Co-authored-by: Vít Ondruch <vondruch@redhat.com>

* Note that as the annocheck binary package is not available on Ubuntu, and it
  is working in progress in Debian, the script uses Fedora container, and
  it requires docker or podman command.
  https://www.debian.org/devel/wnpp/itp.en.html
  https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=926470
* .github/workflows/compilers.yml: Add "gcc-11 annocheck" case.
  To pass the CI, set `TEST_ANNOCHECK_OPTS: "--skip-pie --skip-notes"` for now.
  See <https://bugs.ruby-lang.org/issues/18061>.
* Skip MJIT tests in case of annocheck case.
  The MJIT tests fail in the annocheck case.
  See <https://bugs.ruby-lang.org/issues/18781>.