Emit metadata nodes in post-order. The iterative algorithm from r266709
failed to maintain this property. After understanding my mistake, it
wasn't too hard to write a test with llvm-bcanalyzer (and I've actually
made this change once before: see r220340).
This also reverts the "noisy" testcase change from r266709. That should
have been more of a red flag :/.
Note: The same bug crept into the ValueMapper in r265456. I'm still
working on the fix.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@266947 91177308-0d34-0410-b5e6-96231b3b80d8
e33a1a53cc