Remove #[macro_use] extern crate tracing from rustc_mir_transform.

compiler/rustc_mir_transform/src/sroa.rs

@@ -9,6 +9,7 @@ use rustc_middle::mir::*;
 use rustc_middle::ty::{self, Ty, TyCtxt};
 use rustc_mir_dataflow::value_analysis::{excluded_locals, iter_fields};
 use rustc_target::abi::{FieldIdx, FIRST_VARIANT};
+use tracing::{debug, instrument};
 
 pub struct ScalarReplacementOfAggregates;