Rollup merge of #93018 - pierwill:rm-unused-ord, r=davidtwco

Rollup merge of #93018 - pierwill:rm-unused-ord, r=davidtwco

Remove some unused `Ord` derives based on `Span`

Remove some `Ord`, `PartialOrd` derivations that rely on underlying ordering of `Span`. These ordering traits appear to be unused right now.

If we're going to attempt to remove ordering traits from `Span` as suggested in https://github.com/rust-lang/rust/issues/90317#issuecomment-1013980591, we might want to slowly remove code that depends on this ordering (as opposed to the all-at-once approach in https://github.com/rust-lang/rust/pull/90749 and https://github.com/rust-lang/rust/pull/90408).

cc `@tmiasko` `@cjgillot`