Don't run net_4_0 tests during "make check"

As @marek-safar noted in https://github.com/mono/mono/commit/cf4f10ef51b6de50093354546d1eeec9fbc21f0e#commitcomment-7128403, the IL code
for the 4.0 profile is never used for running (they are just built for having metadata), so it makes no sense to execute 4.0 tests during "make check"