fix(tests): satisfy post-batch clippy checks

Use usize::BITS for the static-CDict ABI offset that Clippy identifies as a bit-width expression. Replace the two MT flush cleanup test closures that independently borrow one vector with Rc<RefCell> probes, preserving the explicit wait-before-release assertions while making the test harness compile.

Test Plan:

- ulimit -v 41943040; CARGO_BUILD_JOBS=1 cargo clippy --manifest-path rust/Cargo.toml --all-targets -- -D warnings

- git diff --cached --check

rust/src/zstd_compress_dictionary.rs

@@ -1115,7 +1115,7 @@ const _: () = {
     assert!(offset_of!(ZSTD_rust_initStaticCDictState, c_params) == 5 * size_of::<usize>());
     assert!(offset_of!(ZSTD_rust_initStaticCDictState, sizing) == 6 * size_of::<usize>());
     assert!(offset_of!(ZSTD_rust_initStaticCDictState, create_workspace) == 7 * size_of::<usize>());
-    assert!(offset_of!(ZSTD_rust_initStaticCDictState, reserve_object) == 8 * size_of::<usize>());
+    assert!(offset_of!(ZSTD_rust_initStaticCDictState, reserve_object) == usize::BITS as usize);
     assert!(offset_of!(ZSTD_rust_initStaticCDictState, move_workspace) == 9 * size_of::<usize>());
     assert!(offset_of!(ZSTD_rust_initStaticCDictState, initialize) == 10 * size_of::<usize>());
     assert!(offset_of!(ZSTD_rust_initStaticCDictState, init) == 11 * size_of::<usize>());

rust/src/zstdmt_compress.rs

@@ -6821,7 +6821,9 @@ mod tests {
             jobIDMask: 0,
             ..ZSTDMT_flushContextProjection::default()
         };
-        let mut error_cleanup = Vec::new();
+        let error_cleanup = Rc::new(RefCell::new(Vec::new()));
+        let wait_cleanup = Rc::clone(&error_cleanup);
+        let release_cleanup = Rc::clone(&error_cleanup);
         let result = unsafe {
             flush_produced_with(
                 context,
@@ -6834,13 +6836,13 @@ mod tests {
                 |_job_id, _projection| panic!("unexpected checksum callback"),
                 |_job_id, _dst_flushed| panic!("unexpected update callback"),
                 |_job_id, _src_size, _c_size| panic!("unexpected completion callback"),
-                || error_cleanup.push("wait"),
-                || error_cleanup.push("release"),
+                move || wait_cleanup.borrow_mut().push("wait"),
+                move || release_cleanup.borrow_mut().push("release"),
             )
         };
         assert_eq!(result.result, ERROR(ZstdErrorCode::Generic));
         assert_eq!(result.outputPos, 0);
-        assert_eq!(error_cleanup, ["wait", "release"]);
+        assert_eq!(&*error_cleanup.borrow(), &["wait", "release"]);
 
         let job = [0x80u8, 0x81, 0x82, 0x83, 0x84, 0x85, 0x86];
         let mut output = [0xa5u8; 8];
@@ -6899,7 +6901,9 @@ mod tests {
             frameChecksumNeeded: 1,
             ..ZSTDMT_flushJobProjection::default()
         };
-        let mut error_cleanup = Vec::new();
+        let error_cleanup = Rc::new(RefCell::new(Vec::new()));
+        let wait_cleanup = Rc::clone(&error_cleanup);
+        let release_cleanup = Rc::clone(&error_cleanup);
         let mut completed = false;
 
         let result = unsafe {
@@ -6921,14 +6925,14 @@ mod tests {
                 },
                 |_job_id, _dst_flushed| panic!("unexpected update callback"),
                 |_job_id, _src_size, _c_size| completed = true,
-                || error_cleanup.push("wait"),
-                || error_cleanup.push("release"),
+                move || wait_cleanup.borrow_mut().push("wait"),
+                move || release_cleanup.borrow_mut().push("release"),
             )
         };
 
         assert_eq!(result.result, ERROR(ZstdErrorCode::DstSizeTooSmall));
         assert_eq!(result.outputPos, 0);
-        assert_eq!(error_cleanup, ["wait", "release"]);
+        assert_eq!(&*error_cleanup.borrow(), &["wait", "release"]);
         assert!(!completed);
         assert_eq!(output, [0xa5; 8]);
     }