[llvm] [BOLT] Fix unrecognized option values for print-sorted-by-order (PR #155613)

[Paschalis Mpeis via llvm-commits]

https://github.com/paschalis-mpeis commented:

Indeed it appears that descending was default with no way to set it?

```
llvm-bolt --dyno-stats --print-sorted-by-order=ascending ..
llvm-bolt: for the --print-sorted-by-order option: Cannot find option named 'ascending'!

llvm-bolt --dyno-stats --print-sorted-by-order=descending ..
llvm-bolt: for the --print-sorted-by-order option: Cannot find option named 'descending'!
```

Not sure if it's easy to add a small lit test or some text example on the PR.

https://github.com/llvm/llvm-project/pull/155613