Summary:
We have the FloatOut pass create exported ids for floated StaticPtr
bindings. The simplifier doesn't try to remove those.

This patch also improves on 7fc20b by making a common definition
collectStaticPtrSatArgs to test for StaticPtr binds.

Fixes #12207.

Test Plan: ./validate

Reviewers: simonpj, austin, bgamari, simonmar, goldfire

Reviewed By: simonpj

Subscribers: thomie

Differential Revision: https://phabricator.haskell.org/D2366

GHC Trac Issues: #12207