After #12732, 6904501173
asserts call k_panic.
Before this, the POSIX arch had its own hack in the
__ASSERT_POST implementation to terminate the process instead
of spining forever.
But the POSIX arch does implement k_panic properly, so there
is no need anymore for this hack.
=> Remove the special treatment for POSIX ARCH
Signed-off-by: Alberto Escolar Piedras <alpi@oticon.com>