GPU: Track buffer migrations and flush source on incomplete copy (#3952)

* Track buffer migrations and flush source on incomplete copy

Makes sure that the modified range list is always from the latest iteration of the buffer, and flushes earlier iterations of a buffer if the data has not been migrated yet.

* Cleanup 1

* Reduce cost for redundant signal checks on Vulkan

* Only inherit the range list if there are pending ranges.

* Fix OpenGL

* Address Feedback

* Whoops

Ryujinx.Graphics.GAL/Multithreading/ThreadedRenderer.cs

@@ -338,6 +338,11 @@ namespace Ryujinx.Graphics.GAL.Multithreading
             return box.Result;
         }
 
+        public ulong GetCurrentSync()
+        {
+            return _baseRenderer.GetCurrentSync();
+        }
+
         public HardwareInfo GetHardwareInfo()
         {
             return _baseRenderer.GetHardwareInfo();