The recent failures in TimeRoutedAliasUpdateProcessorTest. are a result of
the changes to SOLR-11218. The initial fix is easy, but while fixing it I
saw a comment in there about cleaning up when tests.iters is specified > 1.

The assumption was that everything would be cleaned up between runs doesn't
appear to be true for SolrCloud tests. I think one of two things is

1> collections (and perhaps aliases) are simply not cleaned up

2> there is a timing issue, we have waitForCollectionToDisappear in test
code after all.

My question is what are the expectations? It's pretty ugly to require each
test to clean up all changes to ZooKeeper or else fail when test.iters is
set. Plus it violates the expectation that running one test doesn't affect
the other test, even if it's the same test over and over.

So if we think it's an issue with the framework, any clues where to look
would be appreciated.