memcheck/tests/strchr test should not depend on line numbers.

git-svn-id: svn://svn.valgrind.org/valgrind/trunk@13348 a5019735-40e9-0310-863c-91ae7b9d1cf9
For memcheck overlap filter_memcpy str[n]cpy and __GI_str[n]cpy are equal.

git-svn-id: svn://svn.valgrind.org/valgrind/trunk@13349 a5019735-40e9-0310-863c-91ae7b9d1cf9