* Fixes https://github.com/rbenv/ruby-build/issues/1798
* OpenJDK 17 reports:
  $ java -version
  openjdk version "17" 2021-09-14
  There is no dot in the version, so we need to only use the first match from grep -o.
* Clarify it is a minimum required java version, not an exact version.

Add a definition for yjit-dev

Use openssl-1.1.1l

* 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