Remove harvesting of M.E.DependencyModel

The netstandard1.6 configuration of Microsoft.Extensions.DependencyModel
isn't built anymore. Instead the already built matching binary from the
latest available package version is redistributed when packaging the
DependencyModel library.

Also dropping the netstandard1.3 asset and the net451 one as the
minimum supported set of platforms are ones that support netstandard2.0.

In addition to the harvesting removal, cleaning up the src project which
had an unnecessary condition and property set.

Contributes to dotnet#47530

src/libraries/Microsoft.Extensions.DependencyModel/pkg/Microsoft.Extensions.DependencyModel.pkgproj

@@ -4,8 +4,18 @@
     <ProjectReference Include="..\src\Microsoft.Extensions.DependencyModel.csproj">
       <SupportedFramework>net461;netcoreapp2.0;uap10.0.16299;$(AllXamarinFrameworks)</SupportedFramework>
     </ProjectReference>
-    <!-- Elements from previous packages that will be included in the newly built package -->
-    <HarvestIncludePaths Include="lib/net451;lib/netstandard1.3;lib/netstandard1.6" />
   </ItemGroup>
+  <!-- Remove TFMs that aren't supported by the package intentionally anymore. -->
+  <Target Name="_RemoveSupportedFramework"
+          BeforeTargets="ValidateLibraryPackage">
+    <ItemGroup>
+      <SupportedFramework Remove="netcoreapp1.0" />
+      <SupportedFramework Remove="netcoreapp1.1" />
+      <SupportedFramework Remove="netcore50" />
+      <SupportedFramework Remove="uap10.0" />
+      <SupportedFramework Remove="net451" />
+      <SupportedFramework Remove="net46" />
+    </ItemGroup>
+  </Target>
   <Import Project="$([MSBuild]::GetPathOfFileAbove(Directory.Build.targets))" />
 </Project>

src/libraries/Microsoft.Extensions.DependencyModel/src/Microsoft.Extensions.DependencyModel.csproj

@@ -3,10 +3,6 @@
     <TargetFrameworks>netstandard2.0;net461</TargetFrameworks>
     <EnableDefaultItems>true</EnableDefaultItems>
   </PropertyGroup>
-  <PropertyGroup>
-    <!-- Ensure Assemblies are first resolved via targeting pack when targeting net461 -->
-    <AssemblySearchPaths Condition="'$(TargetFramework)' == 'net461'">$(NuGetPackageRoot)\microsoft.targetingpack.netframework.v4.6.1\1.0.1\lib\net461\;$(AssemblySearchPaths)</AssemblySearchPaths>
-  </PropertyGroup>
 
   <ItemGroup>
     <Compile Include="$(CoreLibSharedDir)\System\Numerics\Hashing\HashHelpers.cs"
@@ -17,9 +13,9 @@
     <InternalsVisibleTo Include="Microsoft.Extensions.DependencyModel.Tests" /> 
   </ItemGroup>
 
-  <ItemGroup Condition="$(TargetFramework.StartsWith('net4'))">
+  <ItemGroup Condition="'$(TargetFramework)' == 'net461'">
     <Reference Include="System.Runtime" />
-    <PackageReference Include="System.Runtime.InteropServices.RuntimeInformation" Version="4.3.0" Condition="'$(TargetFramework)' == 'net461'" />
+    <PackageReference Include="System.Runtime.InteropServices.RuntimeInformation" Version="4.3.0" />
   </ItemGroup>
 
   <ItemGroup>
@@ -29,5 +25,4 @@
     <ProjectReference Include="$(LibrariesProjectRoot)System.Text.Encodings.Web\src\System.Text.Encodings.Web.csproj" />
     <ProjectReference Include="$(LibrariesProjectRoot)System.Text.Json\src\System.Text.Json.csproj" />
   </ItemGroup>
-
 </Project>