refactor RawKVClient.java unit tests

[iosmanthus]

Feature Request

Is your feature request related to a problem? Please describe: Currently, tests in RawKVClient is not modularized. baseTest in https://github.com/tikv/client-java/blob/85aa64177c2694835d4c0b5fa277ae25452f9bf2/src/test/java/org/tikv/raw/RawKVClientTest.java#L375 mixes benchmark logic and test logic into one function.

Describe the feature you'd like: Remove the benchmark logic in this test suite and use the benchmark framework to describe the benchmark code: https://github.com/openjdk/jmh.

This also requires a new test suite to cover the basic KV API provided by client-java.

[github-actions[bot]]

This issue is stale because it has been open 30 days with no activity.