coverage: Remove debug code from the instrumentor

compiler/rustc_mir_transform/src/coverage/graph.rs

@@ -1,4 +1,3 @@
-use itertools::Itertools;
 use rustc_data_structures::graph::dominators::{self, Dominators};
 use rustc_data_structures::graph::{self, GraphSuccessors, WithNumNodes, WithStartNode};
 use rustc_index::bit_set::BitSet;
@@ -8,8 +7,6 @@ use rustc_middle::mir::{self, BasicBlock, BasicBlockData, Terminator, Terminator
 use std::cmp::Ordering;
 use std::ops::{Index, IndexMut};
 
-const ID_SEPARATOR: &str = ",";
-
 /// A coverage-specific simplification of the MIR control flow graph (CFG). The `CoverageGraph`s
 /// nodes are `BasicCoverageBlock`s, which encompass one or more MIR `BasicBlock`s.
 #[derive(Debug)]
@@ -324,10 +321,6 @@ impl BasicCoverageBlockData {
     pub fn terminator<'a, 'tcx>(&self, mir_body: &'a mir::Body<'tcx>) -> &'a Terminator<'tcx> {
         &mir_body[self.last_bb()].terminator()
     }
-
-    pub fn id(&self) -> String {
-        format!("@{}", self.basic_blocks.iter().map(|bb| bb.index().to_string()).join(ID_SEPARATOR))
-    }
 }
 
 /// Represents a successor from a branching BasicCoverageBlock (such as the arms of a `SwitchInt`)