[engine] Only request literal Variants for Address objects
Review Request #3724 - Created April 19, 2016 and submitted
Variants are tied to Address objects (parsed from them), so this removes a gross inefficency by only looking up Variants for Address subjects. This is still a special case, it's just a significantly less expensive one.
Unit test times before and after:Before: 157 passed, 1 skipped, 1 xfailed in 100.51 seconds After: 157 passed, 1 skipped, 1 xfailed in 35.27 seconds