Rollup merge of #137302 - compiler-errors:stray-drop-regions, r=matthewjasper

Use a probe to avoid registering stray region obligations when re-checking drops in MIR typeck

Fixes #137288.

See the comment I left on the probe. I'm not totally sure why this depends on *both* an unconstrained type parameter in the impl and a type error for the self type, but I think the fix is at least theoretically well motivated.

r? ```@matthewjasper```

compiler/rustc_infer/src/infer/mod.rs

@@ -950,7 +950,7 @@ impl<'tcx> InferCtxt<'tcx> {
         let inner = self.inner.borrow();
         assert!(!UndoLogs::<UndoLog<'_>>::in_snapshot(&inner.undo_log));
         let storage = inner.region_constraint_storage.as_ref().expect("regions already resolved");
-        assert!(storage.data.is_empty());
+        assert!(storage.data.is_empty(), "{:#?}", storage.data);
         // We clone instead of taking because borrowck still wants to use the
         // inference context after calling this for diagnostics and the new
         // trait solver.