OpenGL: Avoid taking X lock when swapping buffers to reduce lock contention

modules/juce_opengl/native/juce_OpenGL_linux.h

@@ -346,7 +346,6 @@ public:
 
     void swapBuffers()
     {
-        XWindowSystemUtilities::ScopedXLock xLock;
         glXSwapBuffers (display, glxWindow.get());
     }