Fix constructor invocation type inference.

pkg/front_end/testcases/inference/instance_creation_downwards.dart.strong.expect

Index: pkg/front_end/testcases/inference/instance_creation_downwards.dart.strong.expect
diff --git a/pkg/front_end/testcases/inference/instance_creation_downwards.dart.strong.expect b/pkg/front_end/testcases/inference/instance_creation_downwards.dart.strong.expect
new file mode 100644
index 0000000000000000000000000000000000000000..0d8d78f07b43317d4c9e14d10bed2703054c7bad
--- /dev/null
+++ b/pkg/front_end/testcases/inference/instance_creation_downwards.dart.strong.expect
@@ -0,0 +1,17 @@
+library test;
+import self as self;
+import "dart:core" as core;
+
+class A<T extends core::Object> extends core::Object {
+  constructor •(self::B<core::List<self::A::T>> b) → void
+    : super core::Object::•()
+    ;
+}
+class B<T extends core::Object> extends core::Object {
+  constructor •() → void
+    : super core::Object::•()
+    ;
+}
+static method main() → dynamic {
+  self::A<dynamic> x = new self::A::•<dynamic>(new self::B::•<core::List<dynamic>>());
+}