Fix PR#35119 : set_union misbehaves with move_iterators. Thanks to Denis Yaroshevskiy for both the bug report and the fix.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@316914 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed