[core] Don't use atod in Parrot_str_to_num on non-single-byte encoded strings. Closes TT#724.
[core] Don't use atod in Parrot_str_to_num on non-single-byte encoded strings. Closes TT#724.

git-svn-id: 6e74a02f85675cec270f5d931b0f6998666294a3@39287 d31e2699-5ff4-0310-a27c-f18f2fbe73fe

ashgti/parrot,ashgti/parrot,ashgti/parrot,ashgti/parrot,ashgti/parrot,ashgti/parrot,ashgti/parrot