[PM] Add the explicit copy, move, swap, and assignment boilerplate

required by MSVC 2013.

This also makes the repeating pass wrapper assignable. Mildly
unfortunate as it means we can't use a const member for the int, but
that is a really minor invariant to try to preserve at the cost of loss
of regularity of the type. Yet another annoyance of the particular C++
object / move semantic model.

llvm-svn: 277582