Getting the ./pants junit runner to work with Cucumber scenarios.

Review Request #3090 - Created Nov. 6, 2015 and submitted

Garrett Malmquist
2512, 2513, 2515
jsirois, nhoward_tw, zundel
Cucumber Scenarios generate test Descriptions that are unusually
formatted. Cucumber sends the Scenario description as the
"class name", and the step description as the "method name". The
actual test class object is null.

This was causing the junit runner itself to generate NPEs and fail
on some of our internal targets which use Cucumber.

This fixes the problem by making the AntJunitXmlReportListener less
dependent on the specifics of what's stored in the class name and
method name fields.

Added a testproject run by tests/python/pants_test/backend/jvm/tasks/, currently marked as xfail.
It fails currently, but I've confirmed locally that it will pass when we release a new junit runner and upgrade to it.

CI went green here:

John Sirois
John Sirois
John Sirois
Garrett Malmquist
Eric Ayers
Garrett Malmquist
Review request changed

Status: Closed (submitted)

Change Summary:

In 38e33f2a193409b67ed5acaf756d7919258e3cfa Thanks John & Eric