Auto merge of #10103 - ehuss:tree-cycle, r=alexcrichton

Fix a couple issues with cyclic features and dev-dependencies

This fixes two issues with cyclic features and dev-dependencies:

* `cargo tree` would enter an infinite loop for cyclic features.
* The resolver would return a confusing error if a cyclic dev-dependency attempted to enable a feature on its parent that resulted in a cycle.  This fixes it to resolve correctly.

Fixes #10101