[GOLD] Fix tests for powerpc64

[Cary Coutant]

> PowerPC64 defines .TOC. rather than _GLOBAL_OFFSET_TABLE_, and
> what's more, doesn't define it at all unless referenced.  For ELFv1
> ABI the symbol isn't normally referenced, so modify the test to accept
> .TOC. as a variant of _GLOBAL_OFFSET_TABLE_ and 0 or 1 occurrences.
>
> copy_test_relro as written doesn't need copy relocs on PowerPC64.
> PowerPC64 is always PIC.  So, modify copy_test_relro to test that the
> existing vars are in fact read-only directly by deliberately causing a
> sigsegv, and add another couple of vars that do cause copy relocs even
> when PIC.
>
> OK?
>
>         * testsuite/ver_test_8.sh: Accept .TOC. in lieu of
>         _GLOBAL_OFFSET_TABLE_.  Allow zero count.
>         * testsuite/copy_test_relro_1.cc (c, q): New vars.
>         * testsuite/copy_test_relro.cc: Rewrite to test read-only
>         status of variables directly.  Reference new vars in
>         read-only data.

Sorry, my original intent was to accept the non-copy-relocation case
where the variables remained in the shared library, but I kind of lost
track of that when I got around to writing the test. I like your
straightforward approach of just testing that the variables remain
read-only.

This is OK. Thanks!

-cary