Handle redirecting constructors to DillMemberBuilder.

pkg/front_end/test/fasta/redirecting_constructor.dart.direct.expect

Index: pkg/front_end/test/fasta/redirecting_constructor.dart.direct.expect
diff --git a/pkg/front_end/test/fasta/redirecting_constructor.dart.direct.expect b/pkg/front_end/test/fasta/redirecting_constructor.dart.direct.expect
new file mode 100644
index 0000000000000000000000000000000000000000..d3acee0c68a9e29bbabcdbe952ca10f4b106dfe3
--- /dev/null
+++ b/pkg/front_end/test/fasta/redirecting_constructor.dart.direct.expect
@@ -0,0 +1,19 @@
+library;
+import self as self;
+import "dart:core" as core;
+
+class A extends core::Object {
+  constructor •() → void
+    : super core::Object::•()
+    ;
+  static factory fisk() → dynamic
+    invalid-statement;
+}
+class B extends self::A {
+  constructor •() → void
+    : super self::A::•()
+    ;
+}
+static method main() → dynamic {
+  new self::B::•();
+}