Work around clippy warning

Author: webmaster128

libwasmvm/src/error/rust.rs

@@ -297,9 +297,8 @@ mod tests {
 
     #[test]
     fn from_std_str_utf8error_works() {
-        let error: RustError = str::from_utf8(b"Hello \xF0\x90\x80World")
-            .unwrap_err()
-            .into();
+        let broken = b"Hello \xF0\x90\x80World";
+        let error: RustError = str::from_utf8(broken).unwrap_err().into();
         match error {
             RustError::InvalidUtf8 { msg, .. } => {
                 assert_eq!(msg, "invalid utf-8 sequence of 3 bytes from index 6")