Update src/libcore/tests/slice.rs
Update src/libcore/tests/slice.rs

Co-Authored-By: Jack O'Connor <13a330b9fe6700a4154416cd69396fe1fc17c4e9@gmail.com>
aidancully/rust,aidancully/rust,graydon/rust,graydon/rust,graydon/rust,aidancully/rust,aidancully/rust,graydon/rust,graydon/rust,aidancully/rust,graydon/rust,aidancully/rust