Ref counted types missing pointer comparison optimization for eq

[epage]

Arc<str> compares pointers first which normal reference equality checks do not perform.

See https://htmlpreview.github.io/?https://github.com/epage/string-benchmarks-rs/blob/master/runs/2023-10-10/eq/report/index.html for a benchmark showcasing the behavior from this

[polazarus]

Sorry for the delay! Good catch! Really nice work on string Rosetta too

Updated link: https://htmlpreview.github.io/?https://github.com/rosetta-rs/string-rosetta-rs/blob/master/runs/2023-10-10/self_eq/report/index.html