MSBuild disables hard linking when building in Visual Studio

Consider these two property groups inside of MS.Common.CurrentVersion.targets:

- https://github.com/Microsoft/msbuild/blob/90506c8f6c5e4b82a09bafa6ae62a41e9e7367bb/src/Tasks/Microsoft.Common.CurrentVersion.targets#L4171-L4175
- https://github.com/Microsoft/msbuild/blob/90506c8f6c5e4b82a09bafa6ae62a41e9e7367bb/src/Tasks/Microsoft.Common.CurrentVersion.targets#L4154

These will unconditionally override some of the hard link settings when building inside of Visual Studio. This means that hard links are pretty much useless in VS which is typically the primary build scenario for developers.

Here is data from the [Roslyn repository](https://github.com/dotnet/roslyn) on how much benefit we get from this on the command line at least:

| | Build Time | Binaries Size Explorer | Binaries Size DU |
|-|-|-|-|
| No hard link | 4:00 | 13.9GB | 14.9GB |
| Hard links | 3:28 | 13.8GB | 1.5GB |