[PM] Refactor BoundsChecking further to prepare it to be exposed both as
a legacy and new PM pass.

This essentially moves the class state to parameters and re-shuffles the
code to make that reasonable. It also does some minor cleanups along the
way and leaves some comments.

Differential Revision: https://reviews.llvm.org/D39081

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@318124 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed