ut: cpp ut support option zk_host:zk_port

Cpp ut defines zk port 6181 in code. If we want to modify it, we should rebuild the binary files. It's not good for testing.
We should support:
```
./build/bin/xxx_test --port 2181
```

The issue mentions C++ unit tests that hardcode a ZooKeeper port. Look for test binaries in ./build/bin/ that end with _test. The change involves adding command-line argument parsing (like --port) to these test executables, likely in their main() function. Check existing test code for similar argument handling. After modifying, rebuild the test binary and verify it accepts the new port option.

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