Fix NoNodeException in tests

- Suppress org.apache.zookeeper.KeeperException when repositories reset
- Fix zk Stream/Job definition repositories deleteAll()
  - continue on NoNodeException here
- Make delete(), deleteAll() operations in ZKModuleMetadata repos no-op
- Fix streamName in AbstractSingleNodeStreamDeploymentIntegrationTests

Speedup build process

- Support tests to run in parallel
  - Fix some of the tests so that they can run in parallel.
  - Configure maxParallelForks to use available core
  - Increase forkEvery value for spring-xd-dirt tests and for the rest of the tests.
- Modify jvm args for compile and test

polished deleteAll() methods on merge