test: posix: skip nanosleep testcase for ARC HSDK boards

The comparison of cycles we get with k_cycle_get_32 may be
incorrect if counter wrap happened. In case of ARC HSDK and
ARC HSDK4xD platforms we have high counter clock frequency
(500MHz or 1GHz) so counter wrap quite likely to happen if
we wait long enough. As in some test cases we wait more than
1 second, there are significant chances to get false-positive
assertion.

So let's skip nanosleep testcase for ARC HSDK and ARC HSDK4xD
boards.

The proper fix is to use k_cycle_get_64 in this test case,
but we need to provide k_cycle_get_64 support for ARC HSDK and
ARC HSDK4xD platforms first.

Signed-off-by: Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>
Signed-off-by: Evgeniy Paltsev <PaltsevEvgeniy@gmail.com>