Some tests are very load-sensitive as they depend on sleep() calls to
take a precise amount of time. These will randomly fail in the automated
QA, so skip them.
(From OE-Core rev: ea6933d2500827eae5482a32d5037e0429cd096a)
Signed-off-by: Ross Burton <ross.burton@arm.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>