Revert "Resubmit "Add support for advanced number formatting.""

This reverts commits 284436 and 284437 because they still break AArch64 bots:

Value of: format_number(-10, IntegerStyle::Integer, 1)
  Actual: "-0"
  Expected: "-10"

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@284462 91177308-0d34-0410-b5e6-96231b3b80d8
5 files changed