Fix many bugs with closure conversion in checked mode.

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

Index: pkg/kernel/testcases/closures/arity.dart.expect
diff --git a/pkg/kernel/testcases/closures/arity.dart.expect b/pkg/kernel/testcases/closures/arity.dart.expect
index 5a89267f75c00333259a9377b4eb06e7e0bb23f8..bc1353f341fbb48b364dbbaeaae9f90d5adce095 100644
--- a/pkg/kernel/testcases/closures/arity.dart.expect
+++ b/pkg/kernel/testcases/closures/arity.dart.expect
@@ -19,9 +19,9 @@ static method main() → dynamic {
   (MakeClosure<(dynamic, dynamic, [dynamic]) → dynamic>(self::closure#main#function#4, null)).call(1, 2);
   (MakeClosure<(dynamic, dynamic, [dynamic]) → dynamic>(self::closure#main#function#5, null)).call(1, 2, 3);
 }
-static method closure#main#function(Vector #contextParameter, dynamic x, dynamic y, [dynamic z]) → dynamic {}
-static method closure#main#function#1(Vector #contextParameter, dynamic x, dynamic y, dynamic z) → dynamic {}
-static method closure#main#function#2(Vector #contextParameter, dynamic x, dynamic y, {dynamic z}) → dynamic {}
-static method closure#main#function#3(Vector #contextParameter, dynamic x, dynamic y, dynamic z, dynamic w, dynamic v) → dynamic {}
-static method closure#main#function#4(Vector #contextParameter, dynamic x, dynamic y, [dynamic z]) → dynamic {}
-static method closure#main#function#5(Vector #contextParameter, dynamic x, dynamic y, [dynamic z]) → dynamic {}
+static method closure#main#function(dynamic #contextParameter, dynamic x, dynamic y, [dynamic z]) → dynamic {}
+static method closure#main#function#1(dynamic #contextParameter, dynamic x, dynamic y, dynamic z) → dynamic {}
+static method closure#main#function#2(dynamic #contextParameter, dynamic x, dynamic y, {dynamic z}) → dynamic {}
+static method closure#main#function#3(dynamic #contextParameter, dynamic x, dynamic y, dynamic z, dynamic w, dynamic v) → dynamic {}
+static method closure#main#function#4(dynamic #contextParameter, dynamic x, dynamic y, [dynamic z]) → dynamic {}
+static method closure#main#function#5(dynamic #contextParameter, dynamic x, dynamic y, [dynamic z]) → dynamic {}