* Fixes #1786

https://github.com/aws/aws-cli/issues/5234#issuecomment-705831465

* Only do clean_prefix_path for TruffleRuby and rename for clarity,
  since the logic is now TruffleRuby-specific.

Refresh download mirror in GitHub Actions on push

* Testing is done on GitHub Actions which is much faster.

* So the shasums are checked in PRs.

* This is common on Linux where e.g. /bin = /usr/bin and both are in PATH.

* Uses the latest nightly, which is automatically built.

Added JRuby 9.2.18.0

* Unfortunately the original builds were based on incorrect JDK versions,
  these new hashes represent the correct builds based on JDK11.

This for instance allows `RUBY_CONFIGURE_OPTS` to override
what's set by the definition.

For instance `enable_shared` can be disabled with `RUBY_CONFIGURE_OPTS='--disable-shared'`

* Unfortunately the files were changed and reuploaded as there was an
  issue with the gu (GraalVM Component Updater) catalog URL.

Added mruby-3.0.0