Support: Write ScaledNumbers::getAdjusted()

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@211336 91177308-0d34-0410-b5e6-96231b3b80d8
Support: Clean up getRounded() tests

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@211337 91177308-0d34-0410-b5e6-96231b3b80d8