Rollup merge of #54119 - phansch:unit_test_find_best_match_for_name, r=nikomatsakis
Rollup merge of #54119 - phansch:unit_test_find_best_match_for_name, r=nikomatsakis

Add some unit tests for find_best_match_for_name

There were only some UI tests that covered this function.
Since there's more diagnostic work going on, I think it makes
sense to have this unit tested.

aidancully/rust,aidancully/rust,graydon/rust,graydon/rust,aidancully/rust,GBGamer/rust,GBGamer/rust,GBGamer/rust,GBGamer/rust,graydon/rust,aidancully/rust,aidancully/rust,graydon/rust,GBGamer/rust,aidancully/rust,GBGamer/rust,GBGamer/rust,graydon/rust,graydon/rust,GBGamer/rust