Move UseApphost + PackAsTool logic (#3212)

It needs to be inside a target. Since PackAsTool is set in csproj.
And it need to be before Microsoft.NET.Sdk.targets (basically command
target), so "RunCommand" property can use the correct value.

Author: William Li

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

@@ -27,7 +27,6 @@ Copyright (c) .NET Foundation. All rights reserved.
   <PropertyGroup>
     <_ToolsSettingsFilePath>$(BaseIntermediateOutputPath)DotnetToolSettings.xml</_ToolsSettingsFilePath>
     <SuppressDependenciesWhenPacking Condition=" '$(PackAsTool)' == 'true' ">true</SuppressDependenciesWhenPacking>
-    <UseAppHost Condition=" '$(SelfContained)' != 'true' and '$(PackAsTool)' == 'true' ">false</UseAppHost>
   </PropertyGroup>
 
   <Target Name="PackTool" DependsOnTargets="GenerateToolsSettingsFileFromBuildProperty;Publish;_PackToolValidation" Condition=" '$(PackAsTool)' == 'true' ">

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

@@ -104,6 +104,7 @@ Copyright (c) .NET Foundation. All rights reserved.
     <SelfContained Condition="'$(SelfContained)' == '' and '$(RuntimeIdentifier)' != ''">true</SelfContained>
     <SelfContained Condition="'$(SelfContained)' == ''">false</SelfContained>
     <UseAppHost Condition="'$(UseAppHost)' == '' and
+                           ('$(SelfContained)' == 'true' or '$(PackAsTool)' != 'true') and
                            ('$(SelfContained)' == 'true' or
                             ('$(RuntimeIdentifier)' != '' and '$(_TargetFrameworkVersionWithoutV)' >= '2.1') or
                             '$(_TargetFrameworkVersionWithoutV)' >= '3.0')">true</UseAppHost>

src/Tests/Microsoft.NET.ToolPack.Tests/GivenThatWeWantToPackAToolProject.cs

@@ -21,13 +21,15 @@ namespace Microsoft.NET.ToolPack.Tests
     public class GivenThatWeWantToPackAToolProject : SdkTest
     {
         private string _testRoot;
+        private string _targetFrameworkOrFrameworks = "netcoreapp2.1";
 
         public GivenThatWeWantToPackAToolProject(ITestOutputHelper log) : base(log)
         {
         }
 
         private string SetupNuGetPackage(bool multiTarget, [CallerMemberName] string callingMethod = "")
         {
+            
             TestAsset helloWorldAsset = _testAssetsManager
                 .CopyTestAsset("PortableTool", callingMethod + multiTarget)
                 .WithSource()
@@ -36,7 +38,7 @@ private string SetupNuGetPackage(bool multiTarget, [CallerMemberName] string cal
                     XNamespace ns = project.Root.Name.Namespace;
                     XElement propertyGroup = project.Root.Elements(ns + "PropertyGroup").First();
                 })
-                .WithTargetFrameworkOrFrameworks("netcoreapp2.1", multiTarget)
+                .WithTargetFrameworkOrFrameworks(_targetFrameworkOrFrameworks, multiTarget)
                 .Restore(Log);
 
             _testRoot = helloWorldAsset.TestRoot;
@@ -128,6 +130,8 @@ public void It_contains_runtimeconfig_for_each_tfm(bool multiTarget)
         [InlineData(false)]
         public void It_does_not_contain_apphost_exe(bool multiTarget)
         {
+            _targetFrameworkOrFrameworks = "netcoreapp3.0";
+
             var nugetPackage = SetupNuGetPackage(multiTarget);
             using (var nupkgReader = new PackageArchiveReader(nugetPackage))
             {
@@ -141,6 +145,17 @@ public void It_does_not_contain_apphost_exe(bool multiTarget)
                     allItems.Should().NotContain($"tools/{framework.GetShortFolderName()}/any/consoledemo{extension}");
                 }
             }
+
+            var getValuesCommand = new GetValuesCommand(
+               Log,
+               _testRoot,
+               _targetFrameworkOrFrameworks,
+               "RunCommand",
+               GetValuesCommand.ValueType.Property);
+
+            getValuesCommand.Execute();
+            Path.GetExtension(getValuesCommand.GetValues().Single())
+                .Should().NotBe(".exe", "Repro https://github.com/dotnet/cli/issues/11299");
         }
 
         [Theory]