Mocha test reporter is hiding failures in the console output of AzDO

[d3r3kk]

Our current 'custom mocha reporter' is causing problems diagnosing build issues.

The reporter is an extension class of the mocha-junit-reporter and is used to print out logging messages (in an AzDO friendly way) to the console, as well as collect JUnit-style logging output from the mocha test run.

The reporter caches all stdout/stderr during the mocha test run, and flushes it out to the console at the end of the mocha run.

Unfortunately, this causes an issue whenever a test run is aborted early. The flush never occurs, so the console output never gets logged into the AzDO report!

This makes it very difficult to determine the root cause of test failures on AzDO in some cases, and if the reproduction case is not reliable on local developer machines, makes it impossible to correct.

Remove the custom logger mocha-vsts-reporter.js from use and investigate replacements. We may not need this any longer at all as there has been work on the mocha unit tests that are outputting test logs already. (Also, AzDO console output supports colour proplerly now!).

[d3r3kk]

One potential fix: Use the mocha-multiple-reporters extension and 'tee' the output between the current default reporter and to the mocha-junit-reporter.