Single RuntimeIdentifier (without RuntimeIdentifiers): folder layout changed

[xen2]

With such a project file:

<Project Sdk="MSBuild.Sdk.Extras/2.0.85">
  <PropertyGroup>
    <TargetFrameworks>netstandard2.0</TargetFrameworks>
    <RuntimeIdentifier>win7-x64</RuntimeIdentifier>
  </PropertyGroup>
</Project>

Note that there are no RuntimeIdentifiers (there is only a single runtime)

Behavior of previous versions of MSBuild.Sdk.Extras (2.0.54)
nupkg contains a lib/netstandard2.0 folder (it only built a runtimes/ folder if RuntimeIdentifiers was set)

Behavior of new versions of MSBuild.Sdk.Extras (2.0.85)
nupkg contains a runtimes/win7-x64/lib/netstandard2.0 folder

I was wondering if new behavior was intentional or if it's a regression.
If regression, I can submit a PR to revert to the old behavior.
If not, I would like to submit a PR to make it configurable through a MSBuild variable.