Redirect all redistributed dlls

[cdmihai]

Redistributed dlls appear in the swr and corext nuspec files.

We need to redirect them as per the comment in app.config: https://github.com/Microsoft/msbuild/blob/exp/net472/src/MSBuild/app.config#L43

[rainersigwald]

This is now enforced by #7153.