Fix Rust beta compiler errors 1.78.0-beta.1 (#5439)

* remove redundant imports

* fix test

* contains key

* fmt

* Merge branch 'unstable' into fix-beta-compiler

testing/ef_tests/src/decode.rs

@@ -5,7 +5,7 @@ use std::fs::{self};
 use std::io::Write;
 use std::path::Path;
 use std::path::PathBuf;
-use types::{BeaconState, EthSpec};
+use types::BeaconState;
 
 /// See `log_file_access` for details.
 const ACCESSED_FILE_LOG_FILENAME: &str = ".accessed_file_log.txt";