implement few AVX-512 unsigned convert instructions

git-svn-id: svn://svn.code.sf.net/p/bochs/code/trunk@12034 6c8e4198-a580-4521-a02f-c9ae86df1db9
bugfix

git-svn-id: svn://svn.code.sf.net/p/bochs/code/trunk@12035 6c8e4198-a580-4521-a02f-c9ae86df1db9
remove accidentally committed code

git-svn-id: svn://svn.code.sf.net/p/bochs/code/trunk@12036 6c8e4198-a580-4521-a02f-c9ae86df1db9