Disable loopy-jacob test on old gcc version
Disable loopy-jacob test on old gcc version

This one consumes too much memory and fails the validation, but it compiles fine
with a modern gcc or clang, so let's just blacklist it.

pombredanne/pythran,pombredanne/pythran,serge-sans-paille/pythran,pombredanne/pythran,serge-sans-paille/pythran