Better scoring for loop breakers; fixes simplifier loop in nofib/minimax

Better scoring for loop breakers; fixes simplifier loop in nofib/minimax

See Note [Inline candidates] in OccurAnal.  We were getting a recursive
loop exposed, which led to infinite inlinings.  Doesn't bite much, but
was obviously wrong.

I've change the "scoring order" for loop breakers, which could possibly
have a performance impact on other programs.  A full nofib run exposed
a 0.00% change in allocation in any nofib program, so I don't think it's
likely, but keep an eye out.