Jim Ferenczi 02ab9112a9 Fix spurious failures in AsyncSearchIntegTestCase (#56026)
Async search integration tests are subject to random failures when:
  * The test index has more than one replica.
  * The request cache is used.
  * Some shards are empty.
  * The maintenance service starts a garbage collection when node is closing.

They are also slow because the test index is created/populated on each
test method.

This change refactors these integration tests in order to:
  * Create the index once for the entire test suite.
  * Fix the usage of the request cache and replicas.
  * Ensures that all shards have at least one document.
  * Increase the delay of the maintenance service garbage collection.

Closes #55895
Closes #55988
2020-05-11 15:03:03 +02:00
..