[FLINK-16535][table] rename BatchTableSink#emitDataSet to BatchTableSink#consumeDataSet, and return DataSink

[godfreyhe]

What is the purpose of the change

*To solve buffer problem, BatchTableEnvironment should generate Plan based on DataSinks. However, BatchTableSink#emitDataSet returns void now. So this pr aim to solve this: rename BatchTableSink#emitDataSet to BatchTableSink#consumeDataSet (aligns with StreamTableSink#consumeDataStream) and return DataSink. This is an incompatible change *

Brief change log

• rename BatchTableSink#emitDataSet to BatchTableSink#consumeDataSet, and return DataSink

Verifying this change

This change is already covered by existing tests, such as org.apache.flink.table.catalog.CatalogTableITCase, org.apache.flink.table.api.TableEnvironmentITCase, etc..

Does this pull request potentially affect one of the following parts:

• Dependencies (does it add or upgrade a dependency): (yes / no)
• The public API, i.e., is any changed class annotated with @Public(Evolving): (yes / no)
• The serializers: (yes / no / don't know)
• The runtime per-record code paths (performance sensitive): (yes / no / don't know)
• Anything that affects deployment or recovery: JobManager (and its components), Checkpointing, Kubernetes/Yarn/Mesos, ZooKeeper: (yes / no / don't know)
• The S3 file system connector: (yes / no / don't know)

Documentation

• Does this pull request introduce a new feature? (yes / no)
• If yes, how is the feature documented? (not applicable / docs / JavaDocs / not documented)

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Last check on commit b9be34a (Tue Apr 07 13:33:04 UTC 2020)

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[wuchong]

LGTM.