HttpClient.GetAsync fails with 302 with https if URI redirects on CoreCLR

[Aditya Patwardhan]

When the HTTP URI has a redirect, we get a status code 302. This is a security feature and the code needs to work around it.

More context here: https://github.com/dotnet/corefx/issues/12171#issuecomment-250359676

[Jianyun]

It's not supported redirect from https to http for the security considerations.