Replace ADDITIONAL_MAKE_CLEAN_FILES with ADDITIONAL_CLEAN_FILES in modules

In modules, this replaces

• the directory property ADDITIONAL_MAKE_CLEAN_FILES with
• the directory property ADDITIONAL_CLEAN_FILES,

which is supported by more generators.

In the WarnUnusedCliUnused test, ADDITIONAL_MAKE_CLEAN_FILES is replaced with an unset() statement, which make the test work on more generators.