Change from ArrayBuilder => SharedPools for pooling inside AddBracePa…

…irsAsync (#75630)

It's pretty common for this array to exceed the size threshold supported by ArrayBuilder (128). For the files I'm testing on, the size supported by SharedPools (512) works much better.

Noticed this due to allocations in the editor's scrolling speedometer test, where it was showing up as 1.5% of allocations during scrolling.

src/Features/Core/Portable/BracePairs/IBracePairsService.cs

@@ -8,6 +8,7 @@
 using Microsoft.CodeAnalysis.Host;
 using Microsoft.CodeAnalysis.LanguageService;
 using Microsoft.CodeAnalysis.PooledObjects;
+using Microsoft.CodeAnalysis.Shared.Extensions;
 using Microsoft.CodeAnalysis.Text;
 
 namespace Microsoft.CodeAnalysis.BracePairs;
@@ -46,9 +47,11 @@ public async Task AddBracePairsAsync(
         Document document, TextSpan span, ArrayBuilder<BracePairData> bracePairs, CancellationToken cancellationToken)
     {
         var root = await document.GetSyntaxRootAsync(cancellationToken).ConfigureAwait(false);
-        using var _ = ArrayBuilder<SyntaxNodeOrToken>.GetInstance(out var stack);
 
-        stack.Add(root);
+        using var pooledStack = SharedPools.Default<Stack<SyntaxNodeOrToken>>().GetPooledObject();
+        var stack = pooledStack.Object;
+
+        stack.Push(root);
 
         while (stack.TryPop(out var current))
         {