[Piglit] Allow junit to be used for summary generation

[Mark Janes]

baker.dylan.c at gmail.com writes:

> This series updates the junit backend to allow it to properly load junit
> and convert it back into piglit's internal representation, thus allowing
> it to be summarized using the piglit summary tools
>
> There is still some work that needs to be done beyond this, most of the
> platform metadata isn't stored yet and restored, but I have a plan for
> that. I have some other refactoring work that I think will make that
> easier, and I'd like to get there before landing that.
>
> This is enough to be able to compare junit and json results using the
> console and html summaries.

I don't have a use case for comparing junit and json.  If anyone tried
to compare json to our junit, they would see lots of differences because
json does not respect the "expected-failures" filter.  That filter will
also be unusable for json, because of the same test name character
conversion.

> There is a caveat here, and that's patch 3. To compare json and junit we
> need to be able to restore the names of the junit tests to *exactly*
> what they were before, and currently we don't have a way to reverse the
> '.' -> '_' conversion. My proposal is to change '.' into '___', which is
> very unlikely in a real test name (though we could change it to almost
> anything that would be unique). This may break some existing setup
> (Mark, I think this will probably break some of our expected fail/crash
> data).

It seems to me that it will be simpler for everyone to disallow
junit/json comparisons.  I just need a way for users to visualize a
dozen junit test files for disparate platforms and test suites.