conflicts: Fix edgecases in the Go port of ResolveConflicts
The Go port of ResolveConflicts has two edgecases which it treats differently than the Ruby port, which causes QA tests to fail when its feature flag is default-enabled. This MR fixes both of these issues and default-enables the port again. While default-enabling the port right away may feel a bit forced, we've already got the port enabled in production anyway.
Part of #3289 (closed)