Fix -Wdeprecated warnings due to the use of copy ops on SCEVPredicate derived class...

Fix -Wdeprecated warnings due to the use of copy ops on SCEVPredicate derived class objects

SCEVUnionPredicate is copied constructed here: lib/Transforms/Scalar/LoopDistribute.cpp:793
and move assigned (which can use the base class's copy ctor just
fine/without extra cost (I'd add it if it weren't for MSVC's issues
meaning = default is insufficient)) here: lib/Transforms/Utils/LoopVersioning.cpp:46

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@252537 91177308-0d34-0410-b5e6-96231b3b80d8