Add minimal support for Dwarf 5.

This is not full support for dwarf 5, this merely treats a Dwarf 5
version as Dwarf 4. There are new dwarf ops that are not supported yet,
but this minimally support should allow unwinding to work if those
ops are not present.

Bug: 127355724

Test: New Unit tests pass.
Change-Id: I35b24fbcb15a64acd49e1e0b6890dff4456ee6fd