fixed XSAVE to match spec, implemented first look into XINUSE. TODO: use XINUSE to optimize XSAVEOPT as well

git-svn-id: svn://svn.code.sf.net/p/bochs/code/trunk@12245 6c8e4198-a580-4521-a02f-c9ae86df1db9
implemented INIT optimization for XSAVEOPT instruction

git-svn-id: svn://svn.code.sf.net/p/bochs/code/trunk@12246 6c8e4198-a580-4521-a02f-c9ae86df1db9