remove redundant imports

detects redundant imports that can be eliminated.

for #117772 :

In order to facilitate review and modification, split the checking code and
removing redundant imports code into two PR.

compiler/rustc_query_system/src/query/job.rs

@@ -18,7 +18,6 @@ use std::num::NonZeroU64;
 #[cfg(parallel_compiler)]
 use {
     parking_lot::{Condvar, Mutex},
-    rayon_core,
     rustc_data_structures::fx::FxHashSet,
     rustc_data_structures::{defer, jobserver},
     rustc_span::DUMMY_SP,