Spurious timeout starting to run tests on Windows

[alexcrichton]

http://buildbot.rust-lang.org/builders/auto-win-gnu-64-nopt-t/builds/4063/steps/test/logs/stdio
https://gist.github.com/alexcrichton/cc7b4a7e30cb53268dca0b98779b42cf

Problem at least in the above example is that stdtest printed that it was going to run tests and then it just locked up. This may be related to specifically just stdtest, but I know I've seen this before, so wanted to open an issue about it.

[alexcrichton]

Closing as we've moved off buildbot, and praying we won't ever see this on AppVeyor!