Spark: test cleanup - eliminate unnecessary table refreshes

[wypoon]

TestRewriteDataFilesAction has helper createTable and createTablePartitioned methods that create a Table instance, write to the table, and return the Table instance. However, as the write is done using the DataFrame API and not through the Table, the Table instance that is returned is stale. This is bad design and a trap for unwary new users of the methods who want to add tests. The trap is made worse by the verification helper methods shouldHaveFiles and shouldHaveSnapshots (which take the Table as an argument) doing a Table::refresh before performing its work, so if one looks at some existing test method that calls createTable followed by shouldHaveFiles as a model, one does not see the hidden call to Table::refresh.
The Table should be refreshed before it is returned, so it has all the changes. The side-effecting Table::refresh calls should be removed from verification helper methods. Once this is done, some new Table::refresh calls need to be added. However, I found many unnecessary Table::refresh calls (probably added defensively due to being once bitten, twice shy) and have removed them.
I also found and removed unnecessary Table::refresh calls in TestRewritePositionDeleteFilesAction.

[singhpk234]

LGTM, thanks @wypoon !

seems like we have been doing this for a while now : #4502

[huaxingao]

Thanks @wypoon for the PR! Thanks @ebyhr @singhpk234 for the review!

[wypoon]

Thanks @huaxingao @ebyhr and @singhpk234 for reviewing!