[Chapel Merge] Remove KNL locale model vestiges

Branch: refs/heads/main
Revision: 8aa87506c21b357dfd0a0c62af1459d60f827884
Author: ronawho
Link: Remove KNL locale model vestiges by ronawho · Pull Request #21907 · chapel-lang/chapel · GitHub
Log Message:
Remove KNL locale model vestiges (#21907)

Remove some support missed in #15832

Compare: Comparing 09b73c6833ca69fd139c5c02f9c9e54ce21f2c9d...c9fbb603db9501c34960d8bfcbe58196377c9aa1 · chapel-lang/chapel · GitHub

Diff:
M doc/rst/usingchapel/chplenv.rst
D runtime/include/localeModels/knl
M util/test/chpl_launchcmd.py
D util/test/prediff-for-knl_unexpected_cache_size
https://github.com/chapel-lang/chapel/pull/21907.diff