GHC.Unit.State: Data.Map --> GHC.Types.Unique.Map

Swap all the Data.Maps in GHC.Unit.State for GHC.Unique.UniqMap.

In pursuit of #22426 (closed)

Marking as draft until:

• Fix one failing test
• squash with commit message referencing 22426 and marking the perf tests as failing
• upstream the GHC.Types.Unique.Map API changes in haddock. (I've converted nonDetEltsUniqMap to nonDetUniqMapToList so that the Unique Map API follows the conventions in GHC.Unique.FM). IMHO haddock shouldn't even know about GHC.Types.Unique.Map but c'est la vie.
• reduce max allocations. I think this is just a matter of adding INLINEABLE or specializing the functions that operate on the unique map This will be a separate MR