[SCEV] Use move semantics in ScalarEvolution::setRange

Summary: This makes setRange take ConstantRange by rvalue reference since most callers were passing an unnamed temporary ConstantRange. We can then move that ConstantRange into the DenseMap caches. For the callers that weren't passing a temporary, I've added std::move to to the local variable being passed.

Reviewers: sanjoy, mzolotukhin, efriedma

Reviewed By: sanjoy

Subscribers: takuto.ikuta, llvm-commits

Differential Revision: https://reviews.llvm.org/D32943

llvm-svn: 302371