8024261: xrender: improve performance of small fillRect operations

Reviewed-by: prr, bae

src/solaris/classes/sun/java2d/xr/XRCompositeManager.java

@@ -284,10 +284,15 @@ public class XRCompositeManager {
     public void XRRenderRectangles(XRSurfaceData dst, GrowableRectArray rects) {
         if (xorEnabled) {
             con.GCRectangles(dst.getXid(), dst.getGC(), rects);
+        } else {
+            if (rects.getSize() == 1) {
+                con.renderRectangle(dst.getPicture(), compRule, solidColor,
+                        rects.getX(0), rects.getY(0), rects.getWidth(0), rects.getHeight(0));
             } else {
                 con.renderRectangles(dst.getPicture(), compRule, solidColor, rects);
             }
         }
+    }
 
     public void compositeBlit(XRSurfaceData src, XRSurfaceData dst, int sx,
             int sy, int dx, int dy, int w, int h) {