This PR introduces YJIT, a just-in-time compiler built using a Lazy Basic Block Versioning (LBBV) compiler architecture. For more details about the technique, please refer to Maxime’s published paper and recorded talks: ECOOP 2015 paper: https://arxiv.org/pdf/1411.0352.pdf ECOOP 2015 talk: https://www.youtube.com/watch?v=S-aHBuoiYE0 RubyKaigi 2021 talk: https://www.youtube.com/watch?v=PBVLf3yfMs8