Window autoWatch not working

Hello,

`autoWatch` stopped working for me in 0.12.31 and 0.12.32.
It doesn't "see" files change even when `usePolling` is `true`.

It worked with the same config file (except some reporter settings) before updating, but I can't remember the last version that worked.

Any clues?

Start by reproducing the issue with Karma 0.12.31 or 0.12.32, the reported configuration, autoWatch enabled, and usePolling set to true. Compare behavior with an earlier working version if available; done means file changes are detected and trigger the expected test reruns.

Written by the indexing model from the issue text.