Mark standalone job non-voting/remove from gate

The standalone job at present has a high chance of failure
due to two separate things occuring:

1) The deployed nodes from raid tests can be left in a dirty state
   as the raid configuration remains and is chosen as the root
   device for the next deployment. IF this is chosen by any job,
   such as rescue or a deployment test that attempts to login,
   then the job fails with unable to ssh. The fix for this is
   in the ironic-tempest-plugin but we need to get other fixes
   into stablilize the gate first.
   https://review.opendev.org/#/c/757141/
2) Long running scenarios run in cleaning such as deployment with
   RAID in the standalone suite can encounter conditions where
   the conductor tries to send the next command along before the
   present configuration command has completed. An example is
   downloading the image is still running, while a heartbeat
   has occured in the background and the conductor then seeks
   to perform a second action. This then causes the entire
   deployment to fail, even though it was transitory.
   This should be a relatively easy fix.
   https://review.opendev.org/759906

Change-Id: I6b02be0fa353daac90abf2b1576800c0710f651e

zuul.d/project.yaml

@@ -10,8 +10,10 @@
     check:
       jobs:
         - ironic-tox-unit-with-driver-libs
-        - ironic-standalone
-        - ironic-standalone-redfish
+        - ironic-standalone:
+            voting: false
+        - ironic-standalone-redfish:
+            voting: false
         - ironic-tempest-functional-python3
         - ironic-grenade
         - ironic-grenade-multinode-multitenant:
@@ -47,8 +49,6 @@
       queue: ironic
       jobs:
         - ironic-tox-unit-with-driver-libs
-        - ironic-standalone
-        - ironic-standalone-redfish
         - ironic-tempest-functional-python3
         - ironic-grenade
         # removing from voting due to end of cycle gate instability.