SOLR-5652: Make test more deterministicly random, and increase logging to try and track down strange test failure (merge r1560219)

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/branches/branch_4x@1560220 13f79535-47bb-0310-9956-ffa450edef68
SOLR-5650: When a replica becomes a leader, only peer sync with other replicas that last published an ACTIVE state.

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/branches/branch_4x@1560223 13f79535-47bb-0310-9956-ffa450edef68
LUCENE-5099 - QueryNode should have the ability to detach from its node parent

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SOLR-5476 hardened a bit

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SOLR-5476 needs a reliable way to restart Overseer

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LUCENE-5377: IW.addIndexes(Dir[]) causes silent index corruption

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SOLR-5594: Allow FieldTypes to specify custom PrefixQuery behavior (merge r1560412)

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LUCENE-5413: remove LuceneTestCase.PREFLEX_IMPERSONATION_IS_ACTIVE

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SOLR-5657: When a SolrCore starts on HDFS, it should gracefully handle HDFS being in safe mode.

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/branches/branch_4x@1560554 13f79535-47bb-0310-9956-ffa450edef68
tests: try harder to not kill the last replica in a shard

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