This lean 3 extension crashes the runTest when you close all document windows

[lovettchris]

See this build output.

It seems to fail randomly with Uncaught Error: write EPIPE from various places in the code.

1. t.InfoProvider.handleServerRequest
2. t.InfoProvider.handleMessage
3. t.RoiManager.
4. t.DocViewProvider.offerToOpenProjectDocumentation

The CI test seems to be passing most of the time, but if you run npm run test in the test folder of this PR you will see it pass once, but the second and most of the subsequent runs will fail with long stack traces.

This is the screen shot at the point of the test crash: