Rollup merge of #80072 - richkadel:llvm-coverage-counters-2.2.1, r=tmandry

Fixed conflict with drop elaboration and coverage

See
https://github.com/rust-lang/rust/issues/80045#issuecomment-745733339

Coverage statements are moved to the beginning of the BCB. This does
also affect what's counted before a panic, changing some results, but I
think these results may even be preferred? In any case, there are no
guarantees about what's counted when a panic occurs (by design).

r? `@tmandry`

FYI `@wesleywiser` `@ecstatic-morse`

compiler/rustc_mir/src/transform/coverage/mod.rs

@@ -310,7 +310,7 @@ impl<'a, 'tcx> Instrumentor<'a, 'tcx> {
             inject_statement(
                 self.mir_body,
                 counter_kind,
-                self.bcb_last_bb(bcb),
+                self.bcb_leader_bb(bcb),
                 Some(make_code_region(file_name, &self.source_file, span, body_span)),
             );
         }
@@ -470,7 +470,7 @@ fn inject_statement(
             code_region: some_code_region,
         }),
     };
-    data.statements.push(statement);
+    data.statements.insert(0, statement);
 }
 
 // Non-code expressions are injected into the coverage map, without generating executable code.