[PATCH] Revert "[PECOFF] Add atoms to the PassManager file"

[Shankar Kalpathi Easwaran]

  All of my questions were coming from how the atom got into the PassManager file. It was hard to figure it out. Making it explicitly do that and doing it in one place makes it much simpler and cleaner in my perspective. Like now, you would need an additional step to set ordinals, you will need to go through different sort of assumptions too on what atom comes before what atom and so on and so forth.

http://llvm-reviews.chandlerc.com/D2069