Fix for checkout —theirs or checkout —ours not working if theirs or ours was a deleted node.
Fixed some issues with handling deleted features while resolving merge conflicts.
Fixed incorrect exceptions in unit tests.
Merge remote-tracking branch 'origin/pr/540'
Revert "Fixed incorrect exceptions in unit tests."

This reverts commit 69352838800b6be8cceffb4b7139e79c53aa9856.