Use pooled memory and avoid memory copies (#6691)

* perf: use ByteMemoryPool

* feat: KPageTableBase/KPageTable new methods to read and write `ReadOnlySequence<byte>`

* new: add IWritableBlock.Write(ulong, ReadOnlySequence<byte>) with default impl

* perf: use GetReadOnlySequence() instead of GetSpan()

* perf: make `Parcel` IDisposable, use `ByteMemoryPool` for internal allocation, and make Parcel consumers dispose of it

* remove comment about copySize

* remove unnecessary Clear()

src/Ryujinx.Memory/IWritableBlock.cs

@@ -1,9 +1,25 @@
 using System;
+using System.Buffers;
 
 namespace Ryujinx.Memory
 {
     public interface IWritableBlock
     {
+        /// <summary>
+        /// Writes data to CPU mapped memory, with write tracking.
+        /// </summary>
+        /// <param name="va">Virtual address to write the data into</param>
+        /// <param name="data">Data to be written</param>
+        /// <exception cref="InvalidMemoryRegionException">Throw for unhandled invalid or unmapped memory accesses</exception>
+        void Write(ulong va, ReadOnlySequence<byte> data)
+        {
+            foreach (ReadOnlyMemory<byte> segment in data)
+            {
+                Write(va, segment.Span);
+                va += (ulong)segment.Length;
+            }
+        }
+
         void Write(ulong va, ReadOnlySpan<byte> data);
 
         void WriteUntracked(ulong va, ReadOnlySpan<byte> data) => Write(va, data);