Bug 631081: correct alignment padding when offsets cancel each other; conservative version (r pending=kpalacz and wmaddox).
Bug 631081: correct alignment padding when offsets cancel each other; conservative version (r pending=kpalacz and wmaddox).

Note that this version of the patch deliberately does not address the
16-byte case, in order to reduce risk since that component has not
been reviewed.  (There is a version of the patch that handles both
cases posted on the Bugzilla ticket.)

pnkfelix/tamarin-redux,pfgenyun/tamarin-redux,pnkfelix/tamarin-redux,pfgenyun/tamarin-redux,pnkfelix/tamarin-redux,pnkfelix/tamarin-redux,pfgenyun/tamarin-redux,pfgenyun/tamarin-redux,pfgenyun/tamarin-redux,pnkfelix/tamarin-redux,pnkfelix/tamarin-redux,pfgenyun/tamarin-redux,pfgenyun/tamarin-redux,pfgenyun/tamarin-redux,pnkfelix/tamarin-redux