Add more stats about infer pipeline

[chrisdone-artificial]

stat: parse = 7.332 ms
stat: cycle_detect = 12.33 ms
stat: desugar = 10.17 ms
  stat: elaborate = 260.6 μs
  stat: unify = 139.8 ms
  stat: zonk = 214.5 ms
stat: infer = 354.6 ms
stat: check = 1.071 ms