[CodeGen] Print target index operands as target-index(target-specific) + 8 in both MIR and debug output

Work towards the unification of MIR and debug output by printing `target-index(target-specific) + 8` instead of `<ti#0+8>` and `target-index(target-specific) + 8` instead of `<ti#0-8>`.

Only debug syntax is affected.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@320565 91177308-0d34-0410-b5e6-96231b3b80d8
4 files changed