We mustn't emit the DT_PLTGOT entry in `.dynamic` in a statically-linked
PIE, because there's no dl to relocate it (and `std.pie.relocate`, or
the PIE relocator in libc, won't touch it). In that case, there cannot
be any PLT entries, so there's no point emitting the `.got.plt` section
at all. If we just don't create that section, `link.Elf` already knows
not to add the DT_PLTGOT entry to `.dynamic`.

Co-authored-by: Jacob Young <jacobly0@users.noreply.github.com>