The initAtoms function now only uses the `elf_file` parameter for
reporting linker error messages, making it easier to see that the
function has no data dependencies other than the Object struct itself,
making it easier to parallelize or otherwise move that logic around.

Also removed an indirect call via `addExtra` since we already know the
atom's file is the current Object instance. All calls to `Atom.addExtra`
should be audited for similar reasons.

Also removed unjustified use of `inline fn`.