Fix processHeapClosureForDead CONSTR_NOCAF case:
Fix processHeapClosureForDead CONSTR_NOCAF case:

CONSTR_NOCAF was introduced with 55d535da10d as a replacement for
CONSTR_STATIC and CONSTR_NOCAF_STATIC, however, as explained in Note
[static constructors], we copy CONSTR_NOCAFs (which can also be seen in
evacuate) during GC, and they can become dead, like other CONSTR_X_Ys.
processHeapClosureForDead is updated to reflect this.

Reviewers: bgamari, simonmar, erikd

Subscribers: thomie, carter

GHC Trac Issues: #7836

Differential Revision: https://phabricator.haskell.org/D4567

sdiehl/ghc,sdiehl/ghc,sdiehl/ghc,sdiehl/ghc,sdiehl/ghc,sdiehl/ghc,sdiehl/ghc