check for duplicated stack addresses by JimLee168

Based on https://code.google.com/p/jpcsp/source/detail?r=3569

Fix WWE SmackDown! vs. RAW 2006,2007,2008 booting
Fix #6671

2006 Modify log: https://gist.github.com/sum2012/a74a7199dcb3058fa5d8
Does this correctly fix ?
https://github.com/sum2012/ppsspp/commit/b852661a7f54955f7a225624012c4ec7c2f057a8