remove some clippy lints from the list that we do not even trigger any more

Author: RalfJung

src/tools/miri/src/lib.rs

@@ -32,9 +32,7 @@
     clippy::derived_hash_with_manual_eq,
     clippy::too_many_arguments,
     clippy::type_complexity,
-    clippy::single_element_loop,
     clippy::bool_to_int_with_if,
-    clippy::box_default,
     clippy::needless_question_mark,
     clippy::needless_lifetimes,
     clippy::too_long_first_doc_paragraph,