IntervalIterator: Add move semantics rather than relying on broken implicit copy ctor (found with -Wdeprecated)

We were just getting lucky because the copy ctor would be elided by RVO.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@232297 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed