[WIP] Added test to reproduce a problem with schema evolution

[sbernauer]

What is the purpose of the pull request

Add some testcases for schema evolution. Reproduce a problem we faced.

Verify this pull request

This change added tests and can be verified as follows:

mvn -DskipITs -Dscala-2.12 -DfailIfNoTests=false -Dtest=TestHoodieDeltaStreamer#testSchemaEvolution clean test

Committer checklist

• Has a corresponding JIRA in PR title & commit

• Commit message is descriptive of the change

• CI is green

• Necessary doc changes done or have another open PR

• For large changes, please consider breaking it into sub-tasks under an umbrella JIRA.

[vinothchandar]

cc @codope can you take care of this? i.e either add as valid test case (may be it passed now with the recent fixes) or consider this part of the new design

[hudi-bot]

CI report:

• 2f3953a UNKNOWN

Bot commands

@hudi-bot supports the following commands:

• @hudi-bot run travis re-run the last Travis build
• @hudi-bot run azure re-run the last Azure build

[codope]

cc @codope can you take care of this? i.e either add as valid test case (may be it passed now with the recent fixes) or consider this part of the new design

@vinothchandar This PR can be closed. I have included the tests and verified that the master works for those scenarios.

[sbernauer]

Thanks @codope for your work!
The most relevant part of the tests got included with #2927
Thanks for adding the other part!