Merge topic 'test-cxxmodules-split'

9da070b31f Tests/CXXModulesCompile: shorten `non-trivial-collation-order` tests
93449833ff RunCMake/CXXModulesCompile: split into 3 variants

Acked-by: Kitware Robot <kwrobot@kitware.com>
Merge-request: !12098