Keep large file regression test fast

tests/integration_smoke.rs

@@ -1027,7 +1027,7 @@ fn native_file_copy_recursive_round_trip() {
     fs::create_dir_all(src.join("nested")).unwrap();
     fs::write(src.join("root.txt"), b"root file\n").unwrap();
     fs::write(src.join("nested/child.txt"), b"child file\n").unwrap();
-    let large_payload: Vec<u8> = (0..2 * 1024 * 1024)
+    let large_payload: Vec<u8> = (0..128 * 1024)
         .map(|index| (index % 251) as u8)
         .collect();
     fs::write(src.join("large.bin"), &large_payload).unwrap();