Remove CONSTR_STATIC

Summary:
We currently have two info tables for a constructor

* XXX_con_info: the info table for a heap-resident instance of the
  constructor, It has type CONSTR, or one of the specialised types like
  CONSTR_1_0

* XXX_static_info: the info table for a static instance of this
  constructor, which has type CONSTR_STATIC or CONSTR_STATIC_NOCAF.

I'm getting rid of the latter, and using the `con_info` info table for
both static and dynamic constructors.  For rationale and more details
see Note [static constructors] in SMRep.hs.

I also removed these macros: `isSTATIC()`, `ip_STATIC()`,
`closure_STATIC()`, since they relied on the CONSTR/CONSTR_STATIC
distinction, and anyway HEAP_ALLOCED() does the same job.

Test Plan: validate

Reviewers: bgamari, simonpj, austin, gcampax, hvr, niteria, erikd

Subscribers: thomie

Differential Revision: https://phabricator.haskell.org/D2690

GHC Trac Issues: #12455