Note that support for rvalue references does not imply support
for the full set of move-related STL operations.
I've preserved support for an odd little thing in insert() where
we're trying to support inserting a new element from an existing
one. If we actually want to support that, there's a lot more we
need to do: insert can call either grow or push_back, neither of
which is safe against this particular use pattern.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@155979 91177308-0d34-0410-b5e6-96231b3b80d8