Revert "Auto merge of #89709 - clemenswasser:apply_clippy_suggestions_2, r=petrochenkov"

The PR had some unforseen perf regressions that are not as easy to find.
Revert the PR for now.

This reverts commit 6ae8912a3e, reversing
changes made to 86d6d2b738.

compiler/rustc_data_structures/src/graph/implementation/mod.rs

@@ -206,11 +206,17 @@ impl<N: Debug, E: Debug> Graph<N, E> {
         AdjacentEdges { graph: self, direction, next: first_edge }
     }
 
-    pub fn successor_nodes(&self, source: NodeIndex) -> impl Iterator<Item = NodeIndex> + '_ {
+    pub fn successor_nodes<'a>(
+        &'a self,
+        source: NodeIndex,
+    ) -> impl Iterator<Item = NodeIndex> + 'a {
         self.outgoing_edges(source).targets()
     }
 
-    pub fn predecessor_nodes(&self, target: NodeIndex) -> impl Iterator<Item = NodeIndex> + '_ {
+    pub fn predecessor_nodes<'a>(
+        &'a self,
+        target: NodeIndex,
+    ) -> impl Iterator<Item = NodeIndex> + 'a {
         self.incoming_edges(target).sources()
     }