Add TaskEnvironment to ProduceContentAssets tests

ProduceContentAssets now uses TaskEnvironment.GetAbsolutePath() in
ProduceContentAsset(). All 4 behavioral tests must provide TaskEnvironment.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: SimaTian

src/Tasks/Microsoft.NET.Build.Tasks.UnitTests/GivenAttributeOnlyTasksGroup6.cs

@@ -336,6 +336,7 @@ public void ProduceContentAssets_WithCompileAsset_ProducesContentItem()
             var task = new ProduceContentAssets
             {
                 BuildEngine = new MockBuildEngine(),
+                TaskEnvironment = TaskEnvironmentHelper.CreateForTest(),
                 ContentFileDependencies = new ITaskItem[] { contentFile },
                 ProjectLanguage = "C#"
             };
@@ -364,6 +365,7 @@ public void ProduceContentAssets_WithNoneBuildAction_ProducesNoContentItem()
             var task = new ProduceContentAssets
             {
                 BuildEngine = new MockBuildEngine(),
+                TaskEnvironment = TaskEnvironmentHelper.CreateForTest(),
                 ContentFileDependencies = new ITaskItem[] { contentFile },
                 ProjectLanguage = "C#"
             };
@@ -392,6 +394,7 @@ public void ProduceContentAssets_WithCopyToOutput_ProducesCopyLocalItem()
             var task = new ProduceContentAssets
             {
                 BuildEngine = new MockBuildEngine(),
+                TaskEnvironment = TaskEnvironmentHelper.CreateForTest(),
                 ContentFileDependencies = new ITaskItem[] { contentFile },
                 ProjectLanguage = "C#"
             };
@@ -431,6 +434,7 @@ public void ProduceContentAssets_FiltersLanguageSpecificAssets()
             var task = new ProduceContentAssets
             {
                 BuildEngine = new MockBuildEngine(),
+                TaskEnvironment = TaskEnvironmentHelper.CreateForTest(),
                 ContentFileDependencies = new ITaskItem[] { csharpFile, vbFile },
                 ProjectLanguage = "C#"
             };

src/Tasks/Microsoft.NET.Build.Tasks/RunCsWinRTGenerator.cs

@@ -211,11 +211,7 @@ protected override string GenerateResponseFileCommands()
     {
         StringBuilder args = new();
 
-<<<<<<< Updated upstream
         IEnumerable<string> referenceAssemblyPaths = ReferenceAssemblyPaths!.Select(static path => path.ItemSpec);
-=======
-        IEnumerable<string> referenceAssemblyPaths = ReferenceAssemblyPaths!.Select(path => (string)TaskEnvironment.GetAbsolutePath(path.ItemSpec));
->>>>>>> Stashed changes
         string referenceAssemblyPathsArg = string.Join(",", referenceAssemblyPaths);
 
         AppendResponseFileCommand(args, "--reference-assembly-paths", referenceAssemblyPathsArg);