Tweaks to enable test-templates to build in VMR (#366)

* Tweaks to enable test-templates to build in VMR
- Correctly check for product build in restore-toolset.ps1
- Don't attempt to build acceptance tests solution if not building tests (single test csproj).

* Update Build.props

* Update Build.props

Update flag

* Update Build.props

eng/Build.props

@@ -5,6 +5,7 @@
     <ProjectToBuild Include="$(MSBuildThisFileDirectory)..\template_feed\NetCoreTestTemplates.sln" />
     <ProjectToBuild Include="$(MSBuildThisFileDirectory)..\Templates\MSTestTemplates.sln" Condition="'$(DotNetBuildSourceOnly)' != 'true'" />
     <ProjectToBuild Include="$(MSBuildThisFileDirectory)..\WizardExtensions\WizardExtensions.sln" Condition="'$(DotNetBuildSourceOnly)' != 'true'" />
-    <ProjectToBuild Include="$(MSBuildThisFileDirectory)..\test\Microsoft.TestTemplates.Acceptance.Tests.sln" Condition="'$(DotNetBuildSourceOnly)' != 'true'" />
+    <!-- Contains only a single test project. Exclude if not building tests. Otherwise nuget will fail to find a project to restore -->
+    <ProjectToBuild Include="$(MSBuildThisFileDirectory)..\test\Microsoft.TestTemplates.Acceptance.Tests.sln" Condition="'$(DotNetBuildTests)' == 'true'" />
   </ItemGroup>
 </Project>

eng/restore-toolset.ps1

@@ -6,7 +6,7 @@ function InitializeCustomSDKToolset {
 
   # The following frameworks and tools are used only for testing.
   # Do not attempt to install them in source build.
-  if ($env:DotNetBuildFromSource -eq "true") {
+  if ($productBuild -or $properties -like "*DotNetBuildRepo=true*") {
     return
   }