[TEST] wait for ongoing recoveries to finish. Flush fails on shards otherwise.
[TEST] verify all threads created by node and client have the node name
closes #6516
Use ordinals for comparison in GlobalOrdinalsStringTermsAggregator.buildAggregation. Closes #6518
[Benchmark] Fix TermsAggregationSearchBenchmark: The `ordinals` execution mode doesn't exist anymore.
don't check .metadata folder for tabs and nocommits
[CLIENT] Remove unnecessary intermediate interfaces

Client, ClusterAdminClient and IndicesAdminClient had corresponding
intermediate `internal` interfaces that are unnecessary and cause
a lot of casting. This commit removes the intermediate interfaces
and uses the super interfaces directly.

This commit also adds Releaseable to `Node` and `Client` in order to
be used with utilities like try / with.

Closes #4355
Closes #6517