Do not block index population.

SchemaIndexHaIT.indexPopulationJobsShouldContinueThroughRoleSwitch() did
not allow population of indexes to complete on all instances. This meant
that one of the instances didn't release the file locks for its indexes,
which in turn lead to the next test failing since it couldn't clear out
the data directory (on Windows).
With the index population completing we can re-enable
onlineSchemaIndicesOnMasterShouldBeBroughtOnlineOnSlavesAfterStoreCopy()

populatingSchemaIndicesOnMasterShouldBeBroughtOnlineOnSlavesAfterStoreCopy()
suffers from other issues (instances do not see one another as available
even after 2 minutes), and can thus not be enabled yet. This is a
different problem and needs separate investigation.