Add stronger infrastructure for CMake-only tests
The CMakeOnly directory added by commit 9a20abf0 (Add infrastructure for CMake-only tests, 2012-01-11) was sufficient only for tests that always run CMake to successfully configure a project. Later commit eeaaffcb (find_package: Test error and warning messages in failure cases, 2012-02-28) added a sample test that covers failure cases. Generalize the above to create new "RunCMake" test infrastructure that can run CMake multiple times for a single project with different variations and check for expected result/stdout/stderr. Allow for both successful and failing CMake project configuration cases. This will be useful to test error messages and failure behavior.