[GOLD] Fix tests for powerpc64

[GOLD] Fix tests for powerpc64

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.

	* 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.