[WIP] Round trip tests

[vamshigv]

Important Read

• Please ensure the GitHub issue is mentioned at the beginning of the PR

What is the purpose of the pull request

(For example: This pull request implements the sync for delta format.)

Brief change log

(for example:)

• Fixed JSON parsing error when persisting state
• Added unit tests for schema evolution

Verify this pull request

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This pull request is a trivial rework / code cleanup without any test coverage.

(or)

This pull request is already covered by existing tests, such as (please describe tests).

(or)

This change added tests and can be verified as follows:

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• Added integration tests for end-to-end.
• Added HudiSchemaEvolutionTest to verify the change.
• Manually verified the change by running a job locally.