This is introduced from b96, might be related to RT-31192. There are some problems with the default setting of prism.text:
1. For CCJ, when font size is 12 to 16, the characters are not displayed for most of the fonts.
2. For Korean, when font size is 12 to 20, the characters are not displayed for most of the fonts.
3. For font "System", Arabic characters are split to single ones.

Above problems don't happen when setting -Dprism.text=coretext .