swift

1132cda8 - [ownership] Move SemanticARCOpts into a separate folder in preparation for splitting into multiple small pseudo-passes.

[ownership] Move SemanticARCOpts into a separate folder in preparation for splitting into multiple small pseudo-passes. SemanticARCOpts keeps on growing with various optimizations attached to a single "optimization" manager. Move it to its own folder in prepation for splitting it into multiple different optimizations and utility files.