Fix clippy::needless_borrow in the compiler

`x clippy compiler -Aclippy::all -Wclippy::needless_borrow --fix`.

Then I had to remove a few unnecessary parens and muts that were exposed
now.

compiler/rustc_const_eval/src/const_eval/eval_queries.rs

@@ -314,7 +314,7 @@ pub fn eval_in_interpreter<'mir, 'tcx>(
     is_static: bool,
 ) -> ::rustc_middle::mir::interpret::EvalToAllocationRawResult<'tcx> {
     let res = ecx.load_mir(cid.instance.def, cid.promoted);
-    match res.and_then(|body| eval_body_using_ecx(&mut ecx, cid, &body)) {
+    match res.and_then(|body| eval_body_using_ecx(&mut ecx, cid, body)) {
         Err(error) => {
             let (error, backtrace) = error.into_parts();
             backtrace.print_backtrace();

compiler/rustc_const_eval/src/const_eval/machine.rs

@@ -200,7 +200,7 @@ impl<'mir, 'tcx: 'mir> CompileTimeEvalContext<'mir, 'tcx> {
                 &caller
                     .file
                     .name
-                    .for_scope(&self.tcx.sess, RemapPathScopeComponents::DIAGNOSTICS)
+                    .for_scope(self.tcx.sess, RemapPathScopeComponents::DIAGNOSTICS)
                     .to_string_lossy(),
             ),
             u32::try_from(caller.line).unwrap(),

compiler/rustc_const_eval/src/const_eval/valtrees.rs

@@ -387,7 +387,7 @@ fn valtree_into_mplace<'tcx>(
 
                 debug!(?place_inner);
                 valtree_into_mplace(ecx, &place_inner, *inner_valtree);
-                dump_place(&ecx, &place_inner);
+                dump_place(ecx, &place_inner);
             }
 
             debug!("dump of place_adjusted:");