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/MemoryManager.cs

@@ -365,6 +365,22 @@ namespace Ryujinx.Graphics.Gpu.Memory
             }
         }
 
+        /// <summary>
+        /// Runs remap actions that are added to an unmap event.
+        /// These must run after the mapping completes.
+        /// </summary>
+        /// <param name="e">Event with remap actions</param>
+        private void RunRemapActions(UnmapEventArgs e)
+        {
+            if (e.RemapActions != null)
+            {
+                foreach (Action action in e.RemapActions)
+                {
+                    action();
+                }
+            }
+        }
+
         /// <summary>
         /// Maps a given range of pages to the specified CPU virtual address.
         /// </summary>
@@ -379,12 +395,15 @@ namespace Ryujinx.Graphics.Gpu.Memory
         {
             lock (_pageTable)
             {
-                MemoryUnmapped?.Invoke(this, new UnmapEventArgs(va, size));
+                UnmapEventArgs e = new(va, size);
+                MemoryUnmapped?.Invoke(this, e);
 
                 for (ulong offset = 0; offset < size; offset += PageSize)
                 {
                     SetPte(va + offset, PackPte(pa + offset, kind));
                 }
+
+                RunRemapActions(e);
             }
         }
 
@@ -398,12 +417,15 @@ namespace Ryujinx.Graphics.Gpu.Memory
             lock (_pageTable)
             {
                 // Event handlers are not expected to be thread safe.
-                MemoryUnmapped?.Invoke(this, new UnmapEventArgs(va, size));
+                UnmapEventArgs e = new(va, size);
+                MemoryUnmapped?.Invoke(this, e);
 
                 for (ulong offset = 0; offset < size; offset += PageSize)
                 {
                     SetPte(va + offset, PteUnmapped);
                 }
+
+                RunRemapActions(e);
             }
         }