Revert "Disable drd/tests/annotate_trace_memory[_xml].vgtest on arm and ppc."

The tests have been changed to not depend on atomic 64bit add_and_fetch.

git-svn-id: svn://svn.valgrind.org/valgrind/trunk@13408 a5019735-40e9-0310-863c-91ae7b9d1cf9