Add test for domain reset

Following https://github.com/autotest/virt-test/pull/1318
Changes:
1. Change cache='default' before test, and do xml recovery at last according to cevich's comments
2. Do change
```
-        session.cmd("touch %s" % tmpfile)
-        status = session.get_command_status("ls %s" % tmpfile)
+        session.cmd_status("rm -rf %s && sync" % tmpfile)
+        status = session.get_command_status("touch %s && ls %s" % (tmpfile, tmpfile))
```
According to yangdongsheng's comments
Signed-off-by: Kyla Zhang <weizhan@redhat.com>