Don't re-export std::ops::ControlFlow in the compiler.

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

@@ -1,6 +1,7 @@
 use super::{DirectedGraph, WithNumNodes, WithStartNode, WithSuccessors};
 use rustc_index::bit_set::BitSet;
 use rustc_index::vec::IndexVec;
+use std::ops::ControlFlow;
 
 #[cfg(test)]
 mod tests;
@@ -86,9 +87,6 @@ where
     }
 }
 
-/// Allows searches to terminate early with a value.
-pub use std::ops::ControlFlow;
-
 /// The status of a node in the depth-first search.
 ///
 /// See the documentation of `TriColorDepthFirstSearch` to see how a node's status is updated