Auto merge of #123165 - oli-obk:no_ord_def_id3, r=cjgillot

Stop sorting `Span`s' `SyntaxContext`, as that is incompatible with incremental

work towards rust-lang/rust#90317

Luckily no one actually needed these to be sorted, so it didn't even affect diagnostics. I'm guessing they'd have been sorted by creation time anyway, so it wouldn't really have mattered.

r? `@cjgillot`