CMake 3.27 deprecates compatibility with CMake < 3.5. Update tests that
do not cover older interfaces to avoid the deprecation warning.
Follow the pattern from:
* commit 7b07ccdd2b (Tests/*Only: Update cmake_minimum_required versions,
2020-06-15, v3.19.0-rc1~629^2~1)
* commit 72e7c45e98 (Tests: Bump CMake minimum required in tests to 2.8.12,
2020-12-22, v3.20.0-rc1~224^2)
* commit f6b4db365a (Tests: bump cmake_minimum_required version to 2.8.12,
2021-04-04, v3.21.0-rc1~372^2)
Also remove explicit `cmake_policy` settings made redundant by the
version.
Since 3.19, CMake generates a deprecation warning when using a minimum
version less than 2.8.12. This eliminates those warnings generated
during tests, which are typically hidden from the user and developer but
are being generated nonetheless.
