shader/other: Implement BAR.SYNC 0x0

Trivially implement this particular case of BAR. Unless games use OpenCL
or CUDA barriers, we shouldn't hit any other case here.

src/video_core/shader/node.h

@@ -228,6 +228,7 @@ enum class OperationCode {
     ThreadId,       /// () -> uint
     ShuffleIndexed, /// (uint value, uint index) -> uint
 
+    Barrier,         /// () -> void
     MemoryBarrierGL, /// () -> void
 
     Amount,