determinism: Deterministic object code with -fllvm
As a follow up to !12680, this ticket tracks the changes left to do in `CmmToLlvm` with respect to object determinism.
In particular, the `MonadGetUnique` instance of `LlvmM` uses `uniqFromTag` to sample a non-deterministic unique from `IO`.
In order to guarantee object determinism when using `-fllvm`, the instance of `MonadGetUnique` for `LlvmM` should be backed by a deterministic unique supply (perhaps by applying the `UniqDSMT` transformer to `LlvmM`?).
issue