I've personally worked at a large tech company and saw widespread A/B testing for things exactly as minute as this type of wording. It wasn't a constant dynamic A/B test that automatically selects the best results but rather a trial period and analysis for changes like this.

I obviously can't speak to this case in particular but for pieces of text that are part of the core user flow (not necessarily true in this case), I'd be shocked if A/B tests weren't going on at any large company.