[Improvement] Avoid unnecessary data copy.

### Code of Conduct

- [X] I agree to follow this project's [Code of Conduct](https://www.apache.org/foundation/policies/conduct)

### Search before asking

- [X] I have searched in the [issues](https://github.com/apache/incubator-uniffle/issues?q=is%3Aissue) and found no similar issues.

### What would you like to be improved?

For MR/Tez, I found that compressedData is extracted to uncompressedData. Then uncompressedData is copy to InMemoryMapOutput::memory. I think the copy process is unnecessary.

### How should we improve?

_No response_

### Are you willing to submit PR?

- [X] Yes I am willing to submit a PR!

Start by tracing the MR/Tez flow from compressedData to uncompressedData and then to InMemoryMapOutput::memory. Confirm where the copy occurs and inspect nearby tests or callers before changing anything. Done means the redundant data copy is removed without changing the resulting in-memory map output or behavior.

Written by the indexing model from the issue text.