Use correct size for address space in BasicAA.

The tests just hit this with a different sized
address space since I haven't figured out how
to use this to break it.

I thought I committed this a long time ago,
and I'm not sure why missing this hasn't caused
any problems.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@194903 91177308-0d34-0410-b5e6-96231b3b80d8
Mention address space related changes in release notes.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@194904 91177308-0d34-0410-b5e6-96231b3b80d8