Rollup merge of #56126 - Turbo87:bench-parse, r=alexcrichton
Rollup merge of #56126 - Turbo87:bench-parse, r=alexcrichton

core/benches/num: Add `from_str/from_str_radix()` benchmarks

This was extracted from #55973

/cc @alexcrichton

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