Insert covariance checks in strong mode.

pkg/kernel/testcases/closures/capture_closure_parameter.dart.expect

Index: pkg/kernel/testcases/closures/capture_closure_parameter.dart.expect
diff --git a/pkg/kernel/testcases/closures/capture_closure_parameter.dart.expect b/pkg/kernel/testcases/closures/capture_closure_parameter.dart.expect
index 2800725260b8a0eb96b1f844e8040bee14c15270..204b5c1f48daaa8821b30cf942e80daa6a6596c8 100644
--- a/pkg/kernel/testcases/closures/capture_closure_parameter.dart.expect
+++ b/pkg/kernel/testcases/closures/capture_closure_parameter.dart.expect
@@ -27,11 +27,11 @@ class Closure#main#foo extends core::Object implements core::Function {
     final mock::Context #context = new mock::Context::•(1);
     #context.parent = #contextParameter;
     #context.[]=(0, null);
-    final dynamic bar = new self::Closure#main#foo#bar::•(#context);
+    final() → dynamic bar = new self::Closure#main#foo#bar::•(#context);
     return bar;
   }
 }
 static method main(core::List<core::String> arguments) → dynamic {
-  final dynamic foo = new self::Closure#main#foo::•(null);
+  final(dynamic) → dynamic foo = new self::Closure#main#foo::•(null);
   foo.call(arguments.[](0)).call();
 }