[rakudo] Fix a couple of bugs in candidate sorting for MMD. One was an off-by-one error. The other was more subtle; we mustn't remove edges from the graph per iteration of the topological sort, otherwise we end up not identifying one candidate as narrower than another, depending on the order they appear in the code.
[rakudo] Fix a couple of bugs in candidate sorting for MMD. One was an off-by-one error. The other was more subtle; we mustn't remove edges from the graph per iteration of the topological sort, otherwise we end up not identifying one candidate as narrower than another, depending on the order they appear in the code.

git-svn-id: 6e74a02f85675cec270f5d931b0f6998666294a3@32527 d31e2699-5ff4-0310-a27c-f18f2fbe73fe

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