GPU: Fix errors handling texture remapping (#4745)

* GPU: Fix errors handling texture remapping

- Fixes an error where a pool entry and memory mapping changing at the same time could cause a texture to rebind its data from the wrong GPU VA (data swaps)
- Fixes an error where the texture pool could act on a mapping change before the mapping has actually been changed ("Unmapped" event happens before change, we need to signal it changed _after_ it completes)

TODO: remove textures from partially mapped list... if they aren't.

* Add Remap actions for handling post-mapping behaviours

* Remove unused code.

* Address feedback

* Nit

src/Ryujinx.Graphics.Gpu/Memory/UnmapEventArgs.cs

@@ -1,14 +1,24 @@
-namespace Ryujinx.Graphics.Gpu.Memory
+using System;
+using System.Collections.Generic;
+
+namespace Ryujinx.Graphics.Gpu.Memory
 {
     public class UnmapEventArgs
     {
         public ulong Address { get; }
         public ulong Size { get; }
+        public List<Action> RemapActions { get; private set; }
 
         public UnmapEventArgs(ulong address, ulong size)
         {
             Address = address;
             Size = size;
         }
+
+        public void AddRemapAction(Action action)
+        {
+            RemapActions ??= new List<Action>();
+            RemapActions.Add(action);
+        }
     }
 }