OffScreen (ara 'remote') images with X11, GLX and WGL pipelines
are effectively not accelerated on non-default GraphicsConfigs.

Here's an example:
Run (on unix with no dga)
 src/share/test/java2d/grayscale/DifferentGCTest/Test
test app with 2d tracing, and create two frames on different screens.
Render to the frame on the first screen, note that the image is
rendered using X11 blit loop:
  sun.awt.X11PMBlitLoops::Blit("Integer BGR Pixmap", SrcNoEa, "Integer BGR Pixmap")
then try to render this image to the frame on the other screen
(uncheck 'render to this panel' checkbox) in the test's panel.
You'll see
sun.java2d.loops.Blit::Blit(IntBgr, SrcNoEa, IntBgr)
sun.java2d.loops.Blit::Blit(IntBgr, SrcNoEa, IntBgr)
sun.awt.X11PMBlitLoops::Blit("Integer BGR Pixmap", SrcNoEa, "Integer BGR Pixmap")

So the image is first rendered to a temp BI, then to the pixmap
created for different GC, and then finally to the screen using
X11 blit loop, and this is happening on every blit.

This defeats any acceleration we may have obtained from using pixmaps.

The same is true for other pipelines.

###@###.### 2004-05-04