[Improve][Test] Add test for ResourceManager to keep task will be deployed in different node

[Hisoka-X]

Purpose of this pull request

1. Refactor AbstractResourceManager::sendToMember, change return type to CompletableFuture not InvocationFuture. (We can create CompletableFuture easy but InvocationFuture not, and InvocationFuture is child class of CompletableFuture. So we can do that)
2. Add FakeResourceManager used to test ResourceManager logic.
3. Add test case to make sure our task will be deployed different node randomly.

Does this PR introduce any user-facing change?

No

How was this patch tested?

add new test.

Check list

• If any new Jar binary package adding in your PR, please add License Notice according
  New License Guide
• If necessary, please update the documentation to describe the new feature. https://github.com/apache/seatunnel/tree/dev/docs
• If you are contributing the connector code, please check that the following files are updated:
  1. Update change log that in connector document. For more details you can refer to connector-v2
  2. Update plugin-mapping.properties and add new connector information in it
  3. Update the pom file of seatunnel-dist
• Update the release-note.

[ruanwenjun]

LGTM