tests/posix/common: Fix filtering for POSIX arch

All these tests where filtered for the whole POSIX
architecture, but quite a few of them can be run in
native_sim.
So let's filter out native_posix(_64) in general,
(allowing other native simulator based targes),
and filter for thsi arch out explicitly the 2 tests
which need NEWLIB as this arch does not provide it.

Signed-off-by: Alberto Escolar Piedras <alberto.escolar.piedras@nordicsemi.no>