Report results of running pandas unit tests in CI and fail the job when necessary

[shwina]

Every PR runs a job called pandas-tests that run the Pandas unit tests using cudf.pandas. Currently, there are two issues with this job:

• the results of those tests aren't reported in the job summary or anywhere convenient to look at
• the job always passes, regardless of how many tests were passed or failed

Ideally, we should post the results as a job summary and fail the job if the number of tests passed relative to the development branch falls below a threshold (say, 0.1%).

[vyasr]

The reporting piece of this was addressed in #15369 and follow-ups. @galipremsagar do we want to do the other part and add a failure condition as well?

[galipremsagar]

We currently use nightly reports as baseline, so we can't have a failure condition based on a threshold as it can swing widely based on the number of PRs being merged on a given day. We can revisit the second part when we have a more accurate(upto-date) branch based baselines.

[vyasr]

Agreed, I don't think we can do this quite yet.