Auto merge of #14100 - eth3lbert:snapbox-features, r=weihanglo

test: migrate features and features(2|_namespaced) to snapbox

### What does this PR try to resolve?

Part of #14039.

Migrate following to snapbox:
- tests/testsuite/features.rs
- tests/testsuite/features2.rs
- tests/testsuite/features_namespaced.rs

Author: bors