VAX/BFD: Do not warn about GOT addend mismatches if no GOT entry is made

VAX/BFD: Do not warn about GOT addend mismatches if no GOT entry is made

Match the condition used in `elf_vax_instantiate_got_entries' for the
creation of GOT entries in the processing of R_VAX_GOT32 relocations in
`elf_vax_check_relocs', removing incorrect warnings about a GOT addend
mismatch like:

./ld-new: tmpdir/got-local-ref-off-r.o: warning: GOT addend of 1 to `bar_hidden' does not match previous GOT addend of 0
./ld-new: tmpdir/got-local-ref-off-r.o: warning: GOT addend of 2 to `bar_hidden' does not match previous GOT addend of 0

and corresponding failures with the test cases newly added here:

FAIL: GOT test (executable hidden reference with offset)
FAIL: GOT test (executable visible reference with offset)

for symbols that are considered local for reasons other than having been
forced local with a version script, which is usually the ELF visibility.
Correct code is produced regardless, but the warning breaks `-Werror'
compilation and may upset people regardless.

Interestingly this shows with executable links only, because in shared
library links code from `elf_link_add_object_symbols' triggers:

	    /* If the symbol already has a dynamic index, but
	       visibility says it should not be visible, turn it into
	       a local symbol.  */
	    switch (ELF_ST_VISIBILITY (h->other))
	      {
	      case STV_INTERNAL:
	      case STV_HIDDEN:
		(*bed->elf_backend_hide_symbol) (info, h, TRUE);
		dynsym = FALSE;
		break;
	      }

that sets `h->forced_local' like with a version script.

Add suitable test cases including disassembly to verify correct code has
been produced where no warnings have been issued, and that warnings do
get issued where necessary.  Do not verify (broken) code produced in the
latter case; we should probably make the warning an error, or preferably
actually start supporting GOT references with different addends as they
appear feasible with explicitly relocated GOT that we use.

	bfd/
	* elf32-vax.c (elf_vax_check_relocs) <R_VAX_GOT32>: Use
	SYMBOL_REFERENCES_LOCAL rather than `h->forced_local' to check
	whether the symbol referred is local or not.

	ld/
	* testsuite/ld-vax-elf/got-local-exe-off-hidden.dd: New test
	dump.
	* testsuite/ld-vax-elf/got-local-exe-off-visible.dd: New test
	dump.
	* testsuite/ld-vax-elf/got-local-lib-off-hidden.dd: New test
	dump.
	* testsuite/ld-vax-elf/got-local-lib-off-visible.ed: New test
	dump.
	* testsuite/ld-vax-elf/got-local-off-external.ed: New test dump.
	* testsuite/ld-vax-elf/got-local-exe-off.xd: New test dump.
	* testsuite/ld-vax-elf/got-local-lib-off.xd: New test dump.
	* testsuite/ld-vax-elf/got-local.ld: New test linker script.
	* testsuite/ld-vax-elf/got-local-aux-off.s: New test source.
	* testsuite/ld-vax-elf/got-local-def-off.s: New test source.
	* testsuite/ld-vax-elf/got-local-ref-off-external.s: New test
	source.
	* testsuite/ld-vax-elf/got-local-ref-off-hidden.s: New test
	source.
	* testsuite/ld-vax-elf/got-local-ref-off-visible.s: New test
	source.
	* testsuite/ld-vax-elf/vax-elf.exp: Run the new tests.