Ruby

[ruby/yarp] Only keep semantic fields in Java, i.e. skip location fields

• Add $YARP_SERIALIZE_ONLY_SEMANTICS_FIELDS to control where to serialize location fields at templating time,
  this way there is no overhead for either case and nothing to check at runtime.
• Add a byte in the header to indicate whether location fields are included as expected.
• Fixes https://github.com/ruby/yarp/issues/807
• Simplify the build-java CI job now that the FFI backend is available so JRuby can serialize.
• Support keeping some location fields which are still needed until there is a replacement

https://github.com/ruby/yarp/commit/fc5cf2df12