[FLINK-12204][jdbc] Improve JDBCOutputFormat ClassCastException

[hequn8128]

What is the purpose of the change

This pull request enriches ClassCastException for JDBCOutputFormat.

Note: I haven't added another wrapper for the exception. Instead, I just modify the ClassCastExceptoin’s error message and throw it. The stack would be more intuitive with less stack layer which I think is more user-friendly.

Brief change log

• Enriches ClassCastException for JDBCOutputFormat with the index information.
• Add tests to verify the enriched information.

Verifying this change

This change added tests and can be verified as follows:

• Added testEnrichedClassCastException to test the enriched exception.

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

• Dependencies (does it add or upgrade a dependency): (no)
• The public API, i.e., is any changed class annotated with @Public(Evolving): (no)
• The serializers: (no)
• The runtime per-record code paths (performance sensitive): (no)
• Anything that affects deployment or recovery: JobManager (and its components), Checkpointing, Yarn/Mesos, ZooKeeper: (no)
• The S3 file system connector: (no)

Documentation

• Does this pull request introduce a new feature? (no)

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• ✅ 1. The [description] looks good.
  • Approved by @fhueske [PMC]
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  • Approved by @fhueske [PMC]
• ❓ 3. Needs [attention] from.
• ✅ 4. The change fits into the overall [architecture].
  • Approved by @fhueske [PMC]
• ✅ 5. Overall code [quality] is good.
  • Approved by @fhueske [PMC]

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[fhueske]

Thanks for the PR @hequn8128!
The changes are good, I'll merge it.

@flinkbot approve all

Thanks, Fabian