test: Improve golang tests with root and disabling cache

This allows golang tests to be marked as root or !root using build tags.
The matching tests are then run as expected using our test runner.

This also disables test caching which is unfriendly to repeated test
running and is an absurd golang default to add.

Lastly this hooks up the testing verbose flag to tests that accept a
debug variable.

These tests aren't enabled on travis yet because of how it installs
golang.

engine/graph/autogroup/autogroup_test.go

@@ -15,6 +15,8 @@
 // You should have received a copy of the GNU General Public License
 // along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
+// +build !root
+
 package autogroup
 
 import (