Hotfix: Attach Test annotation to testDeleteFromTableAtSnapshot

[izchen]

When I cherry-pick, I found that the method testDeleteFromTableAtSnapshot is missing a Test annotation.

[rdblue]

@izchen, why did you close this? It looks like this test should be running. @wypoon, any idea why this tests was disabled?

[wypoon]

Hmm, looks like an oversight on my part when porting the change to v3.0. It should have the @Test annotation. However, I am on vacation, don't have my work machine at hand, and not able to test it at the moment.

[rdblue]

Enjoy your vacation! We'll have to track this down, but I don't think there's a rush.

[izchen]

Why did you close this? It looks like this test should be running.

@rdblue, this UT failed in spark version 3.0. I think this is because the [SPARK-33623][SQL] Add canDeleteWhere to SupportsDelete does not exist in 3.0.

[izchen]

I submitted a PR to fix this: #3840

[wypoon]

@izchen thanks for the explanation. I'd forgotten about the fact that canDeleteWhere was added to SupportsDelete only in Spark 3.1 and is not present in Spark 3.0. The fact that we didn't try to clean up all such differences when we reorganized the Spark support into separate directories tripped me up. I think I inadvertently omitted the @Test annotation for the new test and didn't mean to disable it, but this omission led to the CI passing.