[DynInst_API:] [dyninst/dyninst] d40984: Remove unused Object::getFileName (#1489)

[Tim Haines <noreply@xxxxxxxxxx>]

  Branch: refs/heads/master
  Home:   https://github.com/dyninst/dyninst
  Commit: d40984a42345144c842bc7be469f9f9c9d314be5
      https://github.com/dyninst/dyninst/commit/d40984a42345144c842bc7be469f9f9c9d314be5
  Author: Tim Haines <thaines.astro@xxxxxxxxx>
  Date:   2023-08-18 (Fri, 18 Aug 2023)

  Changed paths:
    M symtabAPI/src/Object-elf.C
    M symtabAPI/src/Object-elf.h

  Log Message:
  -----------
  Remove unused Object::getFileName (#1489)

Its usage was removed by 760bfda6e in 2019. It's also confusing because
it could return either the object's SONAME or the Module's filename.
These two things are not the same.