tests/eas/preliminary: Skip TestSchedDomainFlags when cpu_capacity missing
tests/eas/preliminary: Skip TestSchedDomainFlags when cpu_capacity missing

Some older kernels don't have the cpu_capacity sysfs entry. In that case just
skip the test that needs it.

credp/lisa,mdigiorgio/lisa,bjackman/lisa,credp/lisa,ARM-software/lisa,credp/lisa,arnoldlu/lisa,credp/lisa,mdigiorgio/lisa,ARM-software/lisa,ARM-software/lisa,bjackman/lisa,arnoldlu/lisa,ARM-software/lisa