GPU: Don't wedge when other commands are in FIFO with polyline

Fixes Ridge Racer Type 4.

src/core/gpu_commands.cpp

@@ -94,6 +94,7 @@ void GPU::ExecuteCommands()
             DispatchRenderCommand();
             m_blit_buffer.clear();
             EndCommand();
+            continue;
           }
         }
         break;