This cleans up our `TEST_SSE_SUPPORT` macro to only test
for SSE42 and passes the flags to the CMAKE_C/CXX_FLAGS
the cpu check module needed to move to its own folder since
the flags at the end of a CMakeLists.txt appear to be used
for all targets inside a CMakeLists file and cpu_check cannot
be build with sse42 flags.
This only affects Mac/Linux since MSVC has no buildflags
to target SSE42
Pull Request: https://projects.blender.org/blender/blender/pulls/118468
