Issue a deprecation warning on calls to `cmake_minimum_required` or
`cmake_policy` that set policies based on versions older than 3.5.
Note that the effective policy version includes `...<max>` treatment.
Update the check from commit 5845c218d7 (Deprecate compatibility with
CMake versions older than 2.8.12, 2020-06-12, v3.19.0-rc1~629^2).
Test basic unquoted and quoted argument parsing cases including failure
on an unterminated string and an unterminated command invocation. Also
cover arguments not separated by any spaces, which is accidentally
allowed by the current parser.