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/IRenderer.cs

@@ -29,6 +29,7 @@ namespace Ryujinx.Graphics.GAL
         ReadOnlySpan<byte> GetBufferData(BufferHandle buffer, int offset, int size);
 
         Capabilities GetCapabilities();
+        ulong GetCurrentSync();
         HardwareInfo GetHardwareInfo();
 
         IProgram LoadProgramBinary(byte[] programBinary, bool hasFragmentShader, ShaderInfo info);