Extend QueryStability to handle IntoIterator implementations

Fix adjacent code

Fix duplicate warning; merge test into `tests/ui-fulldeps/internal-lints`

Use `rustc_middle::ty::FnSig::inputs`

Address two review comments

- https://github.com/rust-lang/rust/pull/139345#discussion_r2109006991
- https://github.com/rust-lang/rust/pull/139345#discussion_r2109058588

Use `Instance::try_resolve`

Import `rustc_middle::ty::Ty` as `Ty` rather than `MiddleTy`

Simplify predicate handling

Add more `#[allow(rustc::potential_query_instability)]` following rebase

Remove two `#[allow(rustc::potential_query_instability)]` following rebase

Address review comment

Update compiler/rustc_lint/src/internal.rs

Co-authored-by: lcnr <rust@lcnr.de>

compiler/rustc_errors/src/emitter.rs

@@ -17,7 +17,7 @@ use std::path::Path;
 use std::sync::Arc;
 
 use derive_setters::Setters;
-use rustc_data_structures::fx::{FxHashMap, FxIndexMap, FxIndexSet};
+use rustc_data_structures::fx::{FxIndexMap, FxIndexSet};
 use rustc_data_structures::sync::{DynSend, IntoDynSyncSend};
 use rustc_error_messages::{FluentArgs, SpanLabel};
 use rustc_lexer;
@@ -1853,7 +1853,7 @@ impl HumanEmitter {
                             && line_idx + 1 == annotated_file.lines.len(),
                     );
 
-                    let mut to_add = FxHashMap::default();
+                    let mut to_add = FxIndexMap::default();
 
                     for (depth, style) in depths {
                         // FIXME(#120456) - is `swap_remove` correct?