[ostf] Tests status updated only when all test group complete

Steps:
1. Navigate to Fuel with deployed cluster.
2. Go to Health Status tab.
3. Select ONE group of tests: only Functional, or only HA tests for example, or some another group.
4. Run Tests.

Expected: test statuses will be updated one by one as tests completing.
Actual: test statuses are updated only when all test group done.

Bug impact: waiting for a long group of tests in confusing the user that OSTF tests hanged.

Environemnt:
[root@nailgun ~]# fuel2 fuel-version
openstack_version: mitaka-9.0
release: '9.2'
(updated by following instructions:
following official instructions:
https://docs.mirantis.com/openstack/fuel/fuel-master/release-notes/update-product/update-prerequisites-9-2.html#update-prerequisites-9-2
https://docs.mirantis.com/openstack/fuel/fuel-master/release-notes/update-product/update-master-9-2.html#update-master-9-2)