dotnet publish includes refs directory when no views are compiled

[pranavkm]

Repurposing original issue since that's external. This is a regression compared to 2.0.0

mkdir api
cd api
dotnet new api
dotnet publish

dir /b /ad bin\Debug\netcoreapp2.1\publish
refs

---

Original issue

1. dotnet new mvc
2. dotnet build

There's a refs directory in the bin\debug\netcoreapp2.1 directory containing a slew of files from Microsoft.NETCore.App and Microsoft.AspNetCore.App.

[pranavkm]

cc @DamianEdwards \ @rynowak \ @mkArtakMSFT

Using this issue to track the source.

[pranavkm]

cc @mikeharder

[pranavkm]

Tracking Sdk change via dotnet/sdk#2121

[mikeharder]

@pranavkm: I found another interesting wrinkle to this issue. If I use dotnet new api rather than dotnet new mvc, then the refs folder is also included in the output of dotnet publish. Repro steps:

> mkdir api
> cd api
> dotnet new api
> dotnet publish

> dir /b /ad bin\Debug\netcoreapp2.1\publish
refs