[macosx] Non-AA Serif font always displays as regular - no bold or oblique.

With the "-Dswing.defaultlaf=com.sun.java.swing.plaf.motif.MotifLookAndFeel " option,the typed text is not bold.so the bold font looks like the not bold font.refer to JTextPane-Motif.jpg, but without this option the case is passed refer to JTextPane-Mac.jpg.