machines/run_shared_test: remove HAVE_OPENMP=n with CC=clang
machines/run_shared_test: remove HAVE_OPENMP=n with CC=clang

HAVE_OPENMP should be computed automatically in Makefiles

fishilico/shared,fishilico/shared,fishilico/shared,fishilico/shared,fishilico/shared,fishilico/shared,fishilico/shared