Clone test - The type initializer for 'ManagedHttpSmartSubtransportStream' threw an exception

Hi,

I'm just running the build script on develop branch, on W10 `.\build.ps1' and I get this error on the Clone test:
```
========================================
Git-Clone
========================================
Cloning repo https://github.com/WCOMAB/CakeGitTestRepo.git...
An error occurred when executing task 'Git-Clone'.

----------------------------------------
Teardown
----------------------------------------
Finished running tasks.
Trying to clean up test repo D:/OSS/cake-build/upstream-Cake_Git/TestRepo
Successfully cleaned test repo D:/OSS/cake-build/upstream-Cake_Git/TestRepo
Error: One or more errors occurred.
The type initializer for 'ManagedHttpSmartSubtransportStream' threw an exception.

Inner Exception:
Operation is not supported on this platform.
An error occurred when executing task 'Test'.
```
Is there some setup required for succesfully run the net461 tests?

Thanks,
Simo

Start by running .\build.ps1 on Windows 10 and reproducing the failure in the Clone test. Inspect the net461 test setup and the ManagedHttpSmartSubtransportStream exception; done means identifying whether additional setup is required or the test completes successfully.

Written by the indexing model from the issue text.