Fix incorrect suffix stripping from CPP filenames; include C files as possible sources of test targets.
Fix incorrect suffix stripping from CPP filenames; include C files as possible sources of test targets.

jafyvilla/CMake,shuaibarshad/KAUST-CMake,jafyvilla/CMake,shurikasa/CMake,shurikasa/CMake,shuaibarshad/KAUST-CMake,ptoharia/CMake,shurikasa/CMake,biddisco/CMake,shuaibarshad/KAUST-CMake,biddisco/CMake,jafyvilla/CMake,ptoharia/CMake,shurikasa/CMake,ptoharia/CMake,ptoharia/CMake,biddisco/CMake,shuaibarshad/KAUST-CMake,jafyvilla/CMake,biddisco/CMake