Merge topic 'fileapi-compilerargs'

71a4e34d97 fileAPI: Expose CMAKE_<LANG>_COMPILER_ARG1
1e02926c9a fileAPI: Refactor toolchains schema to prepare for new version
3caa572c05 fileAPI: Output more info for test failures

Acked-by: Kitware Robot <kwrobot@kitware.com>
Merge-request: !11419