[LVI] Move LVILatticeVal class to separate header file (NFC). Summary: This allows sharing the lattice value code between LVI and SCCP (D36656). It also adds a `satisfiesPredicate` function, used by D36656. Reviewers: davide, sanjoy, efriedma Reviewed By: sanjoy Subscribers: mgorny, llvm-commits Differential Revision: https://reviews.llvm.org/D37591 llvm-svn: 314411 GitOrigin-RevId: 8af01573a3d7a3924fc99e4338dd493ad24d694e