Add test to run dump when unixbench is running in guest.

Signed-off-by: Dongsheng Yang <yangds.fnst@cn.fujitsu.com>
utils_test: Add a param copy_only into utils_test.run_autotest.

Add a copy_only param in run_autotest, whose default value is False.
If copy_only is True, run_autotest will not run test on guest and
return the command to caller.

Signed-off-by: Dongsheng Yang <yangds.fnst@cn.fujitsu.com>
utils_test.run_autotest: Add a '--exclude=client/tests/virt/*' in tar command.

When we call run_autotest() function to run a test on guest, if the size of
autotest is too large, test will fail to execute tar command. Sometimes the
reason of huge size is size of virt, virt/shared/images, virt/shared/iso.

As run_autotest function is designed to run tests in autotest/client/tests
out of virt, we need not copy the virt subsystem in to guest.

Signed-off-by: Dongsheng Yang <yangds.fnst@cn.fujitsu.com>
libvirt-bench: rename name of test on cfg to make we can run all libvirt_bench test once.

Signed-off-by: Dongsheng Yang <yangds.fnst@cn.fujitsu.com>