Revert "[gicombiner] Add GIMatchTree and use it for the code generation"

Revert "[gicombiner] Add GIMatchTree and use it for the code generation"

All the windows bots are failing match-tree.td and there's no obvious cause that
I can see. It's not just the %p formatting problem. My best guess is that
there's an ordering issue too but I'll need further information to figure that
out. Revert while I'm investigating.

This reverts commit 64f1bb5cd2c6d69af7c74ec68840029603560238 and 77d4b5f5feff663e70b347516cc4c77fa5cd2a20