Rollup merge of #133326 - nnethercote:rm-DefinitelyInitializedPlaces, r=cjgillot

Remove the `DefinitelyInitializedPlaces` analysis.

Its only use is in the `tests/ui/mir-dataflow/def_inits-1.rs` where it is tested via `rustc_peek_definite_init`.

Also, it's probably buggy. It's supposed to be the inverse of `MaybeUninitializedPlaces`, and it mostly is, except that `apply_terminator_effect` is a little different, and `apply_switch_int_edge_effects` is missing. Unlike `MaybeUninitializedPlaces`, which is used extensively in borrow checking, any bugs in `DefinitelyInitializedPlaces` are easy to overlook because it is only used in one small test.

This commit removes the analysis. It also removes
`rustc_peek_definite_init`, `Dual` and `MeetSemiLattice`, all of which are no longer needed.

r? ``@cjgillot``

compiler/rustc_mir_dataflow/src/framework/mod.rs

@@ -373,16 +373,6 @@ impl<T, S: GenKill<T>> GenKill<T> for MaybeReachable<S> {
     }
 }
 
-impl<T: Idx> GenKill<T> for lattice::Dual<BitSet<T>> {
-    fn gen_(&mut self, elem: T) {
-        self.0.insert(elem);
-    }
-
-    fn kill(&mut self, elem: T) {
-        self.0.remove(elem);
-    }
-}
-
 // NOTE: DO NOT CHANGE VARIANT ORDER. The derived `Ord` impls rely on the current order.
 #[derive(Clone, Copy, Debug, PartialEq, Eq, PartialOrd, Ord)]
 enum Effect {