[TableGen] Fix D90844 introduced non-determinism due to iteration over a...

[TableGen] Fix D90844 introduced non-determinism due to iteration over a std::map over allocated object pointers

993eaf2d (D90844) is still wrong.
The allocated const Record* pointers do not have an order guarantee
so switching from DenseMap to std::map does not help.

ProcModelMapTy = std::map<const Record*, unsigned>

Sort the values instead.