remove redundant imports

detects redundant imports that can be eliminated.

for #117772 :

In order to facilitate review and modification, split the checking code and
removing redundant imports code into two PR.

compiler/rustc_codegen_cranelift/src/analyze.rs

@@ -2,7 +2,6 @@
 
 use rustc_index::IndexVec;
 use rustc_middle::mir::StatementKind::*;
-use rustc_middle::ty::Ty;
 
 use crate::prelude::*;