Properly place the NULL STT_FILE symbol revistited

Properly place the NULL STT_FILE symbol revistited

I was having a little closer look at what is going on here and noticed
that HJ unconditionally emits a NULL STT_FILE symbol before emitting
forced local symbols.  That means we really don't need a second pass
over forced local symbols.  The only reason for two passes is when
some forced local symbol can be emitted before the NULL STT_FILE.  So
I set about removing the second pass, updating the testsuite all over
again.  It's also unnecessary to emit the NULL STT_FILE when no
previous file symbol has been emitted.

bfd/
	PR ld/17975
	* elflink.c (struct elf_outext_info): Remove need_second_pass
	and second_pass.
	(elf_link_output_extsym): Delete code handling second forced
	local pass.  Move code emitting NULL STT_FILE symbol later, so
	that it can be omitted if forced local is stripped.  Don't
	emit the NULL STT_FILE if no file symbols have been output.
	(bfd_elf_final_link): Remove second forced local pass.
	* elf32-ppc.c (add_stub_sym): Set linker_def on linker syms.
	(ppc_elf_size_dynamic_sections): Likewise.
	* elf64-ppc.c (ppc_build_one_stub): Likewise.
	(build_global_entry_stubs): Likewise.
	(ppc64_elf_build_stubs): Likewise.
ld/testsuite/
	PR ld/17975
	* ld-aarch64/gc-tls-relocs.d, * ld-alpha/tlspic.rd,
	* ld-cris/libdso-2.d, * ld-i386/tlsdesc-nacl.rd, * ld-i386/tlsdesc.rd,
	* ld-i386/tlsnopic-nacl.rd, * ld-i386/tlsnopic.rd,
	* ld-i386/tlspic-nacl.rd, * ld-i386/tlspic.rd, * ld-ia64/tlspic.rd,
	* ld-powerpc/tlsexe.r, * ld-powerpc/tlsexetoc.r,
	* ld-powerpc/tlsso.r, * ld-powerpc/tlstocso.r,
	* ld-s390/tlspic.rd, * ld-s390/tlspic_64.rd,
	* ld-sparc/tlssunnopic32.rd, * ld-sparc/tlssunnopic64.rd,
	* ld-sparc/tlssunpic32.rd, * ld-sparc/tlssunpic64.rd,
	* ld-tic6x/shlib-1.rd, * ld-tic6x/shlib-1b.rd, * ld-tic6x/shlib-1r.rd,
	* ld-tic6x/shlib-1rb.rd, * ld-tic6x/shlib-noindex.rd,
	* ld-x86-64/tlsdesc-nacl.rd, * ld-x86-64/tlsdesc.rd,
	* ld-x86-64/tlspic-nacl.rd, * ld-x86-64/tlspic.rd: Update.