starting to implement some AVX512 convert opcodes

git-svn-id: svn://svn.code.sf.net/p/bochs/code/trunk@12031 6c8e4198-a580-4521-a02f-c9ae86df1db9
fix for float32_to_uint32_round_to_zero

git-svn-id: svn://svn.code.sf.net/p/bochs/code/trunk@12032 6c8e4198-a580-4521-a02f-c9ae86df1db9
remove statement with no effect

git-svn-id: svn://svn.code.sf.net/p/bochs/code/trunk@12033 6c8e4198-a580-4521-a02f-c9ae86df1db9