[HUDI-9385] Remove start commit with time

[the-other-tim-brown]

Change Logs

• Remove startCommitWithTime usage outside of tests
• Update methods so only tests can specify a specific time

Impact

• Cleans up methods to ensure users start commit to generate a timestamp instead of supplying an arbitrary value

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

None

Documentation Update

Describe any necessary documentation update if there is any new feature, config, or user-facing change. If not, put "none".

• The config description must be updated if new configs are added or the default value of the configs are changed
• Any new feature or user-facing change requires updating the Hudi website. Please create a Jira ticket, attach the
  ticket number here and follow the instruction to make
  changes to the website.

Contributor's checklist

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

[hudi-bot]

CI report:

• 4c0d723 Azure: SUCCESS

Bot commands

@hudi-bot supports the following commands:

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

[danny0405]

+1, the fix the straight-forward, land it first.