The DWARFLinker library has code to identify ObjC selector names, which is used
by the debug linker to generate accelerator table entries. In the future, we
would like the DWARF verifier to also have access to such code, so that it can
identify these names when verifying accelerator tables (e.g. debug_names).
This patch follows the same intent of D155723, where we also moved code
generating simplified template names.
Since this is moving code around and changing the log, we also replace raw
pointer manipulation with the more expressive
We also change a test so that it verifies its output, and that requires having
dsymutil not write to stdout.