Investigate VSCode-Python-Rolling-CI errors where no test reportfile output is found (catastrophic failures).

[d3r3kk]

Since adding the test to ensure that test report files are output during the build, we've caught 4 instances of these test failure cases: https://vscode-python.visualstudio.com/VSCode-Python/_build/results?buildId=1273&view=logs

Windows, testSingleWorkspace, Python 3.5, 3.6, and 3.7.
Windows, testMultiWorkspace, Python 3.6

Investigate and discover if this is this a failure of the test code, or the actual code. If it is the test code, skip the failing tests and add a new backlog item to fix it. If it is the actual code, add a new backlog issue for this milestone and fix it.