Fix failing test due to nuget package path casing

The package cache lower cases all paths, which no longer matches the
package id as we were previously doing. We need to match in a case-
insensitive way therefore for private assets matching to succeed.

This fixes a broken unit test that was blocking two PRs NuGet#151 and NuGet#150.

Also, fix the nuget package versions at the time of this test authoring,
so we don't accidentally break if newer packages ever change and cause
the expectations to fail.

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

@@ -178,6 +178,7 @@ Copyright (c) .NET Foundation. All rights reserved.
 		</ItemGroup>
 		<PropertyGroup>
 			<_PrivateAssets>@(_PrimaryPackageReference -> '%(PrivateAssets)')</_PrivateAssets>
+			<_ShouldIncludeAssetsRegex>$(_NuGetPackageId)\\.+\\$(_PrivateAssets)\\.*</_ShouldIncludeAssetsRegex>
 		</PropertyGroup>
 
 		<ItemGroup Condition="'$(_PrivateAssets)' == 'all'">
@@ -191,7 +192,7 @@ Copyright (c) .NET Foundation. All rights reserved.
 			<!-- In this case, we only add files that have a matching path to the private assets value. 
 				 i.e. for Mono.Options, PrivateAssets=lib, we'll include the file if its full path contains 
 				 'Mono.Options\*\lib\*', meaning the file is a lib. -->
-			<_InferredPackageFile Include="@(_PrimaryOutputRelatedFile)" Condition="$([System.Text.RegularExpressions.Regex]::IsMatch('%(_PrimaryOutputRelatedFile.FullPath)', '$(_NuGetPackageId)\\.+\\$(_PrivateAssets)\\.*')) == 'true'">
+			<_InferredPackageFile Include="@(_PrimaryOutputRelatedFile)" Condition="$([System.Text.RegularExpressions.Regex]::IsMatch('%(_PrimaryOutputRelatedFile.FullPath)', '$(_ShouldIncludeAssetsRegex)', 'RegexOptions.IgnoreCase')) == 'true'">
 				<Kind>$(PrimaryOutputKind)</Kind>
 				<FrameworkSpecific>$(PrimaryOutputFrameworkSpecific)</FrameworkSpecific>
 			</_InferredPackageFile>

src/Build/NuGet.Build.Packaging.Tests/Scenarios/given_a_library_with_private_assets_reference/a.csproj

@@ -6,15 +6,15 @@
 	</PropertyGroup>
 	<ItemGroup>
 		<PackageReference Include="Mono.Options">
-			<Version>*</Version>
+			<Version>5.3.0</Version>
       <PrivateAssets>all</PrivateAssets>
 		</PackageReference>
 		<PackageReference Include="Newtonsoft.Json">
-			<Version>*</Version>
+			<Version>9.0.1</Version>
       <PrivateAssets>lib</PrivateAssets>
 		</PackageReference>
 		<PackageReference Include="xunit">
-			<Version>*</Version>
+			<Version>2.3.0</Version>
 		</PackageReference>
 	</ItemGroup>
 	<Import Project="$([MSBuild]::GetDirectoryNameOfFileAbove($(MSBuildThisFileDirectory), Scenario.targets))\Scenario.targets" />