Remove the UseCache property and old benchmark (#12962)

I _SWEAR_ I pushed a commit that did this before I merged my other PR,
but either GitHub was having issues, or I was in a fugue state

Author: davidwengier

src/Razor/benchmarks/Microsoft.AspNetCore.Razor.Microbenchmarks/Formatting/DocumentFormattingBenchmark.cs

@@ -92,7 +92,6 @@ public void Setup()
             CSharpSyntaxFormattingOptions = RazorCSharpSyntaxFormattingOptions.Default,
         };
 
-        IndentCache.UseCache = true;
         var changeCount = FormatDocumentCore();
         if (changeCount == 0)
         {
@@ -103,29 +102,12 @@ public void Setup()
     [GlobalCleanup]
     public void Cleanup()
     {
-        IndentCache.UseCache = true;
         _workspace?.Dispose();
     }
 
-    [Benchmark(Baseline = true, Description = "100x full document formatting of Razor file (indent cache on)")]
+    [Benchmark(Baseline = true, Description = "100x full document formatting of Razor file")]
     public int FormatDocument()
     {
-        IndentCache.UseCache = true;
-
-        var totalChangeCount = 0;
-        for (var i = 0; i < FormatOperationCount; i++)
-        {
-            totalChangeCount += FormatDocumentCore();
-        }
-
-        return totalChangeCount;
-    }
-
-    [Benchmark(Description = "100x full document formatting of Razor file (indent cache off)")]
-    public int FormatDocumentWithoutIndentCache()
-    {
-        IndentCache.UseCache = false;
-
         var totalChangeCount = 0;
         for (var i = 0; i < FormatOperationCount; i++)
         {

src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/Formatting/IndentCache.cs

@@ -10,10 +10,6 @@ namespace Microsoft.CodeAnalysis.Razor.Formatting;
 
 internal static class IndentCache
 {
-    // Exists only so benchmarks can compare cached and uncached formatting runs.
-    // Production code should leave this enabled.
-    public static bool UseCache { get; set; } = true;
-
     // Copied from the compilers IndentCache
     internal const int MaxTabCount = 64;
     internal const int MaxSpaceCount = 128;
@@ -59,7 +55,7 @@ public static string GetIndentString(int size, bool insertSpaces, int tabSize)
 
     private static string GetSingleCharacterString(int length, char character, string?[] cache)
     {
-        if (length >= cache.Length || !UseCache)
+        if (length >= cache.Length)
         {
             return new string(character, length);
         }
@@ -77,7 +73,7 @@ private static string GetSingleCharacterString(int length, char character, strin
 
     private static string GetMixedString(int tabCount, int spaceCount)
     {
-        if (tabCount > MaxTabCount || spaceCount > MaxSpaceCountInMixedString || !UseCache)
+        if (tabCount > MaxTabCount || spaceCount > MaxSpaceCountInMixedString)
         {
             return CreateMixedString(tabCount, spaceCount);
         }