HBaseTestingUtility#waitUntilAllRegionsAssigned won't return if it counts "too many" regions

HBaseTestingUtility#waitUntilAllRegionsAssigned does not check if the region it is counting belongs to the table created by the test and will not return if it accidentally counts "too many" regions, for example the regions of the ACL table when security is enabled.

Made an attempt at fixing this as part of HBASE-8209 but broke TestMasterTransitions. Try again here.