Auto merge of #126750 - scottmcm:less-unlikely, r=jhpratt

Stop using `unlikely` in `strict_*` methods

The `strict_*` methods don't need (un)likely, because the `overflow_panic` calls are all `#[cold]`, [meaning](https://llvm.org/docs/LangRef.html#function-attributes) that LLVM knows any branch to them is unlikely without us needing to say so.

r? libs

Author: bors