Mark flaky/failing tests as @Postsubmit.

This is done so that telephony tests can be enabled for presubmit.
All tests not passing at least 95% of the time are marked
@Postsubmit. Test passing metrics are based on
go/tel-nyc-mr1-apct-dashboard and go/tel-master-apct-dashboard.
These tests will be fixed as part of b/29579544.

Bug: 31041734
Change-Id: I5e65e94696b6526eb3c270238fd80795319ea2ff