qemu.tests: Add new test kdump_with_stress

Add netperf/IO stress for kdump.

Signed-off-by: Shuping Cui <scui@redhat.com>
generic.tests.cfg: Update kdump config

kdump test should be linux guest only, so disable windows guest.

Signed-off-by: Shuping Cui <scui@redhat.com>
Merge pull request #14 from spcui/kdump_with_stress

qemu.tests: Add new test kdump_with_stress