drd/tests/std_thread2: Filter out libstdc++ header file line numbers

git-svn-id: svn://svn.valgrind.org/valgrind/trunk@14019 a5019735-40e9-0310-863c-91ae7b9d1cf9
Update.


git-svn-id: svn://svn.valgrind.org/valgrind/trunk@14020 a5019735-40e9-0310-863c-91ae7b9d1cf9