rcutorture: Make kvm-test-1-run-qemu.sh check for alternative output

The kvm-again.sh script, when running locally, can place the QEMU output
into kvm-test-1-run-qemu.sh.out instead of kvm-test-1-run.sh.out.  This
commit therefore makes kvm-test-1-run-qemu.sh check both locations.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>