[Improvement] Make Gravitino/GVFS clients run in a separate JVM apart from tests

### What would you like to be improved?

Currently, Gravitino/GVFS client instances in all ITs are running on the same JVM instance that runs Gavitino test, which will make us hard to identify any issues with the Gravitino client and GVFS client. Like #6462, UTs and ITs can't found any problem but will failed in the test.

Therefore, we should make the Gravitino client and GVFS clients run in a separate JVM.

### How should we improve?

_No response_

Start by locating the Gravitino and GVFS client setup used by the integration tests (ITs), then trace how those clients share the JVM with the tests. Determine how the clients can be launched in separate JVMs and run the affected ITs to verify the isolation and confirm that client failures are exposed independently.

Written by the indexing model from the issue text.