Don't pack reference assemblies or NETStandard library package

This improves our detection of the references that come from NETStandard, which
changed in v2 and was causing additional files to be included in a package.

Fixes NuGet/Home#5800

# Conflicts:
#	src/Build/NuGet.Build.Packaging.Tests/NuGet.Build.Packaging.Tests.csproj

Author: kzu

src/Build/NuGet.Build.Packaging.Tasks/NuGet.Build.Packaging.Inference.targets

@@ -131,7 +131,7 @@ Copyright (c) .NET Foundation. All rights reserved.
 			</_InferredPackageFile>
 
 
-			<_InferredPackageFile Include="@(PackageReference)" Condition="'%(PackageReference.Identity)' != 'NuGet.Build.Packaging' and '%(PackageReference.PrivateAssets)' != 'all'">
+			<_InferredPackageFile Include="@(PackageReference)" Condition="'%(PackageReference.Identity)' != 'NuGet.Build.Packaging' and '%(PackageReference.Identity)' != 'NETStandard.Library' and '%(PackageReference.PrivateAssets)' != 'all'">
 				<Kind>Dependency</Kind>
 			</_InferredPackageFile>
 
@@ -159,9 +159,28 @@ Copyright (c) .NET Foundation. All rights reserved.
 		</ItemGroup>
 	</Target>
 
+	<ItemDefinitionGroup>
+		<ReferencePath>
+			<Facade>false</Facade>
+			<FrameworkFile>false</FrameworkFile>
+			<NuGetPackageId />
+			<Pack />
+		</ReferencePath>
+		<_ReferenceRelatedPaths>
+			<Facade>false</Facade>
+			<FrameworkFile>false</FrameworkFile>
+			<NuGetPackageId />
+			<Pack />
+		</_ReferenceRelatedPaths>
+	</ItemDefinitionGroup>
+
 	<Target Name="_CollectPrimaryOutputRelatedFiles" DependsOnTargets="BuildOnlySettings;ResolveReferences" Returns="@(_PrimaryOutputRelatedFile)">
 		<ItemGroup>
-			<_PrimaryOutputRelatedFile Include="@(ReferencePath);@(_ReferenceRelatedPaths)" />
+			<_PrimaryOutputRelatedFile Include="@(ReferencePath);@(_ReferenceRelatedPaths)"
+                                 Condition="'%(NuGetPackageId)' != 'NETStandard.Library' and 
+                                            '%(Facade)' != 'true' and 
+                                            '%(FrameworkFile)' != 'true' and 
+                                            '%(Pack)' != 'false'"/>
 		</ItemGroup>
 	</Target>
 
@@ -171,7 +190,7 @@ Copyright (c) .NET Foundation. All rights reserved.
 			Returns="@(_InferredPackageFile)"
 			DependsOnTargets="_CollectPrimaryOutputRelatedFiles">
 		<ItemGroup>
-			<_NuGetPackageId Include="@(_PrimaryOutputRelatedFile -> '%(NuGetPackageId)')" />
+			<_NuGetPackageId Include="@(_PrimaryOutputRelatedFile -> '%(NuGetPackageId)')" Condition="'%(NuGetPackageId)' != 'NETStandard.Library'" />
 		</ItemGroup>
 		<PropertyGroup>
 			<_NuGetPackageId>@(_NuGetPackageId -> Distinct())</_NuGetPackageId>

src/Build/NuGet.Build.Packaging.Tests/Scenarios/Scenario.props

@@ -25,7 +25,9 @@
 
 		<!-- Used for Dump/Introspect -->
 		<UseCompiledTasks>true</UseCompiledTasks>
-		
+		<!-- Skip the GitInfo stuff we inherit -->
+		<GitThisAssembly>false</GitThisAssembly>
+
 		<!-- Avoids warnings from Xamarin global imports.-->
 		<!--<ImportByWildcardAfterMicrosoftCommonTargets>false</ImportByWildcardAfterMicrosoftCommonTargets>
 		<ImportByWildcardBeforeMicrosoftCommonTargets>false</ImportByWildcardBeforeMicrosoftCommonTargets>-->

src/Build/NuGet.Build.Packaging.Tests/Scenarios/given_a_packaging_project_with_netstandard/b/b.csproj

@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
 	<PropertyGroup>
-		<TargetFramework Condition="'$(CrossTargeting)' != 'true'">netstandard1.6</TargetFramework>
-		<TargetFrameworks Condition="'$(CrossTargeting)' == 'true'">netstandard1.6;net45</TargetFrameworks>
+		<TargetFramework Condition="'$(SimulateCrossTargeting)' != 'true'">netstandard1.6</TargetFramework>
+		<TargetFrameworks Condition="'$(SimulateCrossTargeting)' == 'true'">netstandard1.6;net45</TargetFrameworks>
 		<ProjectGuid>{BBBBBBBB-BBBB-BBBB-BBBB-BBBBBBBBBBBB}</ProjectGuid>
 	</PropertyGroup>
 

src/Build/NuGet.Build.Packaging.Tests/given_a_packaging_project_with_netstandard.cs

@@ -17,7 +17,7 @@ public void can_get_content_from_referenced_single_targeting_netstandard()
 		{
 			var result = Builder.BuildScenario(nameof(given_a_packaging_project_with_netstandard),
 				target: "GetPackageContents", 
-				properties: new { CrossTargeting = "false" },
+				properties: new { SimulateCrossTargeting = "false" },
 				//verbosity: Microsoft.Build.Framework.LoggerVerbosity.Diagnostic,
 				output: output);
 
@@ -34,7 +34,7 @@ public void can_get_content_from_referenced_cross_targeting_netstandard()
 		{
 			var result = Builder.BuildScenario(nameof(given_a_packaging_project_with_netstandard),
 				target: "GetPackageContents",
-				properties: new { CrossTargeting = "true" },
+				properties: new { SimulateCrossTargeting = "true" },
 				//verbosity: Microsoft.Build.Framework.LoggerVerbosity.Diagnostic,
 				output: output);