Reland "Remove comments and code about ro.boot.slot"

This reverts commit c5f5fd430ad08d0a62e08affbcf827a06e17e213.

Dependencies are now merged.

Bug: 37663204
Bug: 66437505
Change-Id: I84284b6bc37f6aae4096dec73f45ebd85d28ca9d
2 files changed