Implement IEEE-754R 2008 nextUp/nextDown functions in the guise of the function APFloat::next(bool nextDown).

rdar://13852078

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@182945 91177308-0d34-0410-b5e6-96231b3b80d8
3 files changed