UseListOrder: Guarantee that shuffles change use-list order

Change shuffleUseLists() always to change use-list order by rejecting
orders that have no changes.

This is part of PR5680.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@214584 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed