revert test case

Author: DevinR528

tests/ui/macro_use_imports.rs

@@ -4,18 +4,10 @@
 
 use std::collections::HashMap;
 #[macro_use]
-use std::{prelude, sync::Mutex};
-#[macro_use]
-extern crate rustc_session;
+use std::prelude;
 
 fn main() {
-    let _ = Mutex::new(8_u8);
     let _ = HashMap::<u8, u8>::new();
     println!();
-    declare_tool_lint! {
-        pub clippy::TEST_LINT,
-        Warn,
-        "",
-        report_in_external_macro: true
-    }
+
 }