Add test cases for 256-bit --partial-loads-ok=no|yes, by generalising the
128-bit versions.  (Patrick J. LoPresti, lopresti@gmail.com).  Bug 294285.


git-svn-id: svn://svn.valgrind.org/valgrind/trunk@13501 a5019735-40e9-0310-863c-91ae7b9d1cf9