Memory changes 3

General memory improvements to decrease GC pressure and frequency.

Pool big arrays and objects that are created and deleted often.

Skip data copies when they aren't needed.

Inline flag checks to skip unneeded allocations.

From my testing the performance is about the same, but the GC frequency is much lower and collection is faster causing less and smaller spikes.

src/Ryujinx.Memory/Range/NonOverlappingRangeList.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Buffers;
 using System.Collections.Generic;
 using System.Diagnostics;
 using System.Runtime.CompilerServices;
@@ -38,7 +39,7 @@ namespace Ryujinx.Memory.Range
                 index = ~index;
             }
 
-            RangeItem<T> rangeItem = new(item);
+            RangeItem<T> rangeItem = _rangeItemPool.Allocate().Set(item);
             
             Insert(index, rangeItem);
         }
@@ -144,6 +145,8 @@ namespace Ryujinx.Memory.Range
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         private void RemoveAt(int index)
         {
+            _rangeItemPool.Release(Items[index]);
+            
             if (index < Count - 1)
             {
                 Items[index + 1].Previous = index > 0 ? Items[index - 1] : null;
@@ -433,7 +436,7 @@ namespace Ryujinx.Memory.Range
             return (Items[index], Items[endIndex - 1]);
         }
         
-        public RangeItem<T>[] FindOverlapsAsArray(ulong address, ulong size)
+        public RangeItem<T>[] FindOverlapsAsArray(ulong address, ulong size, out int length)
         {
             (int index, int endIndex) = BinarySearchEdges(address, address + size);
 
@@ -441,11 +444,13 @@ namespace Ryujinx.Memory.Range
             
             if (index < 0)
             {
-                result = [];
+                result = null;
+                length = 0;
             }
             else
             {
-                result = new RangeItem<T>[endIndex - index];
+                result = ArrayPool<RangeItem<T>>.Shared.Rent(endIndex - index);
+                length = endIndex - index;
                 
                 Array.Copy(Items, index, result, 0, endIndex - index);
             }