[CodeGen] Unify printing format of debug-location in both MIR and -debug

Use "debug-location" instead of "; dbg:" in MI::print.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@322936 91177308-0d34-0410-b5e6-96231b3b80d8
3 files changed