test/DebugInfo: Convert some tests to MIR

These tests are meant to test dwarf emission (or prolog/epilogue
generation) so we can convert them to .mir and only run the relevant
part of the pipeline.
This way they become independent of changes in earlier passes such as my
planned changes to RegAllocFast.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@345919 91177308-0d34-0410-b5e6-96231b3b80d8
14 files changed