Revert "Reapply "[IR] Move optional data in llvm::Function into a hungoff uselist""

This reverts commit r256093.

This broke lld-x86_64-win7 because of -Werror,-Wc++1y-extensions.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@256094 91177308-0d34-0410-b5e6-96231b3b80d8
8 files changed