Need to get the path to the `dotnet.exe` host in GetRunInformation MSBuild target

We are currently returning dotnet.exe without a path in <Target Name="GenerateRunInformation"> in the Microsoft.DotNet.Core.Sdk.targets file.

We should either:

1. Figure out a way to get to the correct dotnet.exe to call from inside our MSBuild target.
2. Or pass back some sort of indicator to dotnet run that this project should use its host to run the project.

[eerhardt]

For .NET Core MSBuild, it should use the path to the host it was invoked with.

One concern is when MSBuild is running on the desktop framework, but building a .NET Core App. Say, for example, when invoked from VS.

[ViktorHofer]

Reopening as there’s still a TODO in the sdk that points to this tracking issue: https://github.com/dotnet/sdk/blob/3ed908ee77c592bae787ac78f466c3bc0581970a/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Sdk.targets#L728