Improve tracing in OccurAnal
Improve tracing in OccurAnal

One commented out tracing function didn't type check and also show the
scores of loop breaker nodes.

Reviewers: austin, bgamari

Reviewed By: bgamari

Subscribers: rwbarton, thomie

Differential Revision: https://phabricator.haskell.org/D3371

sdiehl/ghc,ezyang/ghc,ezyang/ghc,shlevy/ghc,ezyang/ghc,ezyang/ghc,shlevy/ghc,sdiehl/ghc,sdiehl/ghc,sdiehl/ghc,ezyang/ghc,sdiehl/ghc,shlevy/ghc,sdiehl/ghc,sdiehl/ghc,shlevy/ghc,shlevy/ghc,shlevy/ghc,shlevy/ghc,ezyang/ghc,ezyang/ghc