Rename test RunCMake.{deprecation => message}

It covers message() command cases.  Others could be added later.
message: Document DEPRECATION mode
Merge branch 'deprecation-message' into CheckStructHasMember_CXX

Resolve conflict in Tests/RunCMake/CMakeLists.txt by combining both
changes.
Merge topic 'CheckStructHasMember_CXX' into next

1603fe0 Merge branch 'deprecation-message' into CheckStructHasMember_CXX
faf10d0 message: Document DEPRECATION mode
705d70e Rename test RunCMake.{deprecation => message}