Address code review feedback

- Use PooledObjects.ArrayBuilder for tracking points
- Rename pooledSpans to finalCaretSpans
- Simplify test to use TestHandled helper with markup

Co-authored-by: CyrusNajmabadi <4564579+CyrusNajmabadi@users.noreply.github.com>

Author: Copilot

src/EditorFeatures/CSharp/SplitStringLiteral/SplitStringLiteralCommandHandler.cs

@@ -93,7 +93,7 @@ public bool ExecuteCommandWorker(ReturnKeyCommandArgs args, CancellationToken ca
         // However, we need to track the new caret positions in the original forward order
         // for setting the multi-selection at the end. We use tracking points to automatically
         // adjust positions as the buffer changes.
-        var trackingPoints = new ITrackingPoint[spans.Count];
+        using var _ = PooledObjects.ArrayBuilder<ITrackingPoint>.GetInstance(spans.Count, out var trackingPoints);
 
         var currentIndex = spans.Count - 1;
         foreach (var span in spans.Reverse())
@@ -124,7 +124,7 @@ public bool ExecuteCommandWorker(ReturnKeyCommandArgs args, CancellationToken ca
         // Now set all the caret positions using the multi-selection broker.
         // Get the position of each tracking point in the final snapshot.
         var finalSnapshot = subjectBuffer.CurrentSnapshot;
-        using var pooledSpans = TemporaryArray<SnapshotSpan>.Empty;
+        using var finalCaretSpans = TemporaryArray<SnapshotSpan>.Empty;
 
         foreach (var trackingPoint in trackingPoints)
         {
@@ -137,13 +137,13 @@ public bool ExecuteCommandWorker(ReturnKeyCommandArgs args, CancellationToken ca
 
             if (newCaretPoint != null)
             {
-                pooledSpans.AsRef().Add(new SnapshotSpan(newCaretPoint.Value, 0));
+                finalCaretSpans.AsRef().Add(new SnapshotSpan(newCaretPoint.Value, 0));
             }
         }
 
-        if (pooledSpans.Count > 0)
+        if (finalCaretSpans.Count > 0)
         {
-            textView.SetMultiSelection(pooledSpans.ToImmutableAndClear());
+            textView.SetMultiSelection(finalCaretSpans.ToImmutableAndClear());
         }
 
         return true;

src/EditorFeatures/CSharpTest/SplitStringLiteral/SplitStringLiteralCommandHandlerTests.cs

@@ -1072,39 +1072,16 @@ void M()
     [WpfFact, WorkItem("https://github.com/dotnet/roslyn/issues/64812")]
     public void TestMultiCaretPositionsAreAllSet()
     {
-        var workspaceXml = """
-            <Workspace>
-                <Project Language="C#">
-                    <Document>
+        var inputMarkup = """
             class C
             {
                 void M()
                 {
                     var v = "now is [||]the ti[||]me";
                 }
             }
-                    </Document>
-                </Project>
-            </Workspace>
             """;
 
-        using var workspace = EditorTestWorkspace.Create(workspaceXml);
-        var document = workspace.Documents.Single();
-        var view = document.GetTextView();
-        var textBuffer = view.TextBuffer;
-
-        var originalSnapshot = textBuffer.CurrentSnapshot;
-        var originalSelections = document.SelectedSpans;
-
-        // Set up multi-selection with primary caret at the last position
-        view.SetMultiSelection(originalSelections.Select(selection => selection.ToSnapshotSpan(originalSnapshot)));
-
-        var commandHandler = workspace.ExportProvider.GetCommandHandler<SplitStringLiteralCommandHandler>(nameof(SplitStringLiteralCommandHandler));
-        var result = commandHandler.ExecuteCommand(new ReturnKeyCommandArgs(view, textBuffer), TestCommandExecutionContext.Create());
-
-        Assert.True(result);
-
-        // Verify the expected markup with all caret positions
         var expectedMarkup = """
             class C
             {
@@ -1117,26 +1094,7 @@ void M()
             }
             """;
 
-        MarkupTestFile.GetSpans(expectedMarkup, out var expectedOutput, out var expectedSpans);
-        var actualText = textBuffer.CurrentSnapshot.AsText().ToString();
-
-        // Verify text is correct
-        Assert.Equal(expectedOutput, actualText);
-
-        // Verify all caret positions are set correctly
-        var broker = view.GetMultiSelectionBroker();
-        var selections = broker.AllSelections.ToList();
-        Assert.Equal(expectedSpans.Length, selections.Count);
-
-        // Verify each selection position matches the expected position
-        for (int i = 0; i < expectedSpans.Length; i++)
-        {
-            Assert.Equal(expectedSpans[i].Start, selections[i].Start.Position.Position);
-            Assert.True(selections[i].IsEmpty); // All selections should be carets (zero-length)
-        }
-
-        // Verify the primary (last) caret is at the correct position
-        Assert.Equal(expectedSpans.Last().Start, view.Caret.Position.BufferPosition.Position);
+        TestHandled(inputMarkup, expectedMarkup);
     }
 
     [WpfFact, WorkItem("https://github.com/dotnet/roslyn/issues/40277")]