[HUDI-7965] Clean up SchemaTestUtil code

[usberkeley]

Change Logs

Clean up SchemaTestUtil code, delete duplicate code

Impact

none

Risk level (write none, low medium or high below)

none

Documentation Update

none

Contributor's checklist

• [1] Read through contributor's guide
• [1] Change Logs and Impact were stated clearly
• [1] Adequate tests were added if applicable
• [1] CI passed

[hudi-bot]

CI report:

• 46f8faf Azure: SUCCESS

Bot commands

@hudi-bot supports the following commands:

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