Attempt a complete mlgo regalloc training using gematria as latency predictor

[mtrofin]

Main goals are to:

1. see what's missing.
2. fix what's missing so we have a complete testbed others can use (basically llvm-cm plugin)

We can start with @boomanaiden154 's very simple decompression benchmark and then @virajbshah 's cache missing benchmarks - totally fine if models are overfitting initially.