The RunCMake.get_filename_component test was improved to assert that
each test variable outputted by get_filename_component is or is not
a cache variable, as per the particular test.
Signed-off-by: James Johnston <johnstonj.public@codenest.com>
Set the minimum required version of CMake high enough to avoid the
warning for CMAKE_LEGACY_CYGWIN_WIN32. The warning appears on stderr
and breaks the expected output matching.