Green up tests around GeneratePackageOnBuild

Author: baronfel

src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.PackTool.targets

@@ -49,6 +49,10 @@ Copyright (c) .NET Foundation. All rights reserved.
 
     <!-- inner builds and non-RID-specific outer builds need publish content-->
     <_PackToolPublishDependency Condition=" '$(_ToolPackageShouldIncludeImplementation)' != '' and '$(GeneratePackageOnBuild)' != 'true' and $(IsPublishable) == 'true' ">Publish</_PackToolPublishDependency>
+    <!-- BUT builds that GeneratePackageOnBuild can't directly rely on Publish since Publish would trigger Build, causing an infinite loop. -->
+    <!-- To get around this, we try a bit of a workaround: since we can't set NoBuild=true and call Publish that way, we instead trigger all of the
+         dependencies of the no-build Publish Target, _PublishNoBuildAlternative -->
+    <_PackToolPublishDependency Condition=" '$(_ToolPackageShouldIncludeImplementation)' != '' and '$(GeneratePackageOnBuild)' == 'true' and $(IsPublishable) == 'true' ">$(_PublishNoBuildAlternativeDependsOn)</_PackToolPublishDependency>
 
     <!-- Trigger RID-specific inner builds if RID-specific mode is enabled-->
     <GenerateNuspecDependsOn Condition=" '$(_HasRIDSpecificTools)' == 'true' and '$(PublishAot)' != 'true' ">$(GenerateNuspecDependsOn);_CreateRIDSpecificToolPackages</GenerateNuspecDependsOn>