[.net40] Some tests hangs because of httpListener is waiting for request

[jaasco]

Steps to reproduce:

1. checkout net40 branch
2. update nuget.exe to 4.1.0
   $ cd .nuget
   $ nuget.exe update -self
3. run build.net40.bat

Expected results:
All test would be passed.

Actual results:
xunit.console.clr4.exe hangs when about 17-21 are passed.

In a Visual Studio I found that it hangs on several tests like:
NoErrorIsLoggedWhenHttpEndpointIsDisposed
HttpEndpointDoesNotThrowOnDispose
SecondCallToWithHttpEndportDoesNotThrow
HttpEndportLogsAnErrorIfPortIsOccupied
HttpEndpointDoesNotThrowIfPortIsOccupied
when after httpListener.GetContext() it starts to wait for request in a void ProcessRequests() thread in MetricsHttpListener class. When I send some GET request to appropriate URL the thread goes forward and the test passing well.
How should I pass all tests without sending the http requests by myself?