cmake CXX_HAS_ASAN_UBSAN examples

pmem/pmemkv cmake/helpers.cmake :197 

check_cxx_compiler_flag("-fsanitize=${flag}" CXX_HAS_ASAN_UBSAN)

pmem/libpmemobj-cpp cmake/functions.cmake :83 

check_cxx_compiler_flag("-fsanitize=${flag}" CXX_HAS_ASAN_UBSAN)