Optimize local load TsFile piece dispatch

[Caideyipi]

Summary

• avoid the serialize/deserialize round trip when dispatching LoadTsFilePieceNode to the local DataNode
• allow aligned and non-aligned ChunkData produced by the splitter to write directly by lazily materializing their write state
• add unit coverage for local dispatch identity and direct ChunkData writing without a serde round trip

Tests

• mvn -pl iotdb-core/datanode spotless:apply
• javac --release 8 for changed main classes
• javac --release 8 for added test classes
• git diff --check