bugpoint: Remove implicit ilist iterator conversions, NFC

This is the last of the implicit ilist iterator conversions in LLVM.
Still up for debate whether we let these bitrot back:
http://lists.llvm.org/pipermail/llvm-dev/2015-October/091617.html

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@250852 91177308-0d34-0410-b5e6-96231b3b80d8
3 files changed