Removed Python and NumPy pinning on Cygwin

[radarhere]

Alternative to #7875

Two Cygwin changes

1. Reverts Pin to Python 3.9.16-1 #7762, where Python was pinned to Python 3.9.16-1
2. Removes the pinning of NumPy from NumPy now supports Python 3.12 #7403, but also goes further, and just uses the packaged NumPy. NumPy was originally upgraded in a commit entitled "CI: Try to get Cygwin workflow working.", so if there wasn't another need for this, then perhaps testing the package version is more valuable?

This also decreases the build time from 31m54s to 10m13s.

[DWesl]

Tests pass, and include NumPy. I think 1.21 had problems with unaligned load, but that seems gone now.