build net472 specific dependency manager to make ngen happy

[brettfo]

Internal RPS looks clean. Subsequent VS insertion will require binding redirects for Interactive.DependencyManager.dll added to vsn.exe.config.

[KevinRansom]

Brett in dev16.6 this needs changing: https://github.com/dotnet/fsharp/blob/release/dev16.6/setup/Swix/Microsoft.FSharp.Compiler.MSBuild/Microsoft.FSharp.Compiler.MSBuild.csproj#L97

Might as well do it here in master as well to save the grief of forgetting it in 16.6.

[brettfo]

@KevinRansom Updated PR to include that line, it was missing from master.

[KevinRansom]

@brettfo , yes I know, I had to go looking for it, because, I was sure it must be there :-)

[brettfo]

Also, confirmed that with this change VisualFSharpFull.vsix contains the net472 variant, and loading up that in ILSpy shows the offending types/methods as not present, but they are in the netstandard2.0 one.

[brettfo]

After much pain, the NGEN logs are clean and internal RPS test doesn't list FSharp.Compiler.Private or Interactive.DependencyManager. Once green I'll merge this so it can eventually flow into VS branches.