[kernel] Fix bug with redirecting constructors in closure conversion.

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

Index: pkg/kernel/testcases/closures/contexts_in_field_initializers.dart.expect
diff --git a/pkg/kernel/testcases/closures/contexts_in_field_initializers.dart.expect b/pkg/kernel/testcases/closures/contexts_in_field_initializers.dart.expect
index a7e1b28ebf9a9abab2d95310385f2125077a0105..145e647188f90bdfb3c49456805e39d5687c0330 100644
--- a/pkg/kernel/testcases/closures/contexts_in_field_initializers.dart.expect
+++ b/pkg/kernel/testcases/closures/contexts_in_field_initializers.dart.expect
@@ -12,6 +12,21 @@ class A extends core::Object {
   constructor •(self::X x) → void
     : self::A::x = x, super core::Object::•() {}
 }
+class B extends core::Object {

[Dmitry Stefantsov, 2017/08/16 13:15:00]

As I understand it, the redirecting technique is not required here.  I think,
the output should look somewhat like the following:


```
class B extends core::Object {
  field self::X x;
  constructor •(self::X x) → void
    : self::B::x = x, super core::Object::•() {
    final Vector #context = MakeVector(2);
    #context[1] = x;
    final () → dynamic fn = MakeClosure<() →
dynamic>(self::closure#B#function#fn, #context);
    fn.call();
  }
}
```

[sjindel, 2017/08/16 13:28:56]

It's technically not needed, but the analysis is not yet sophisticated enough to
know that.
We could improve it, but I would rather keep that to a separate CL.

[Dmitry Stefantsov, 2017/08/17 12:59:08]

Ok.  At the first glance, based on the CL description, it seemed to me that this
is exactly the kind of issues the CL is supposed to solve.

[sjindel, 2017/08/17 15:46:04]

This CL is address the correct issue, not the inefficiency of the extra function
call.

+  field self::X x;
+  constructor •(self::X x) → void
+    : final Vector #context = MakeVector(2), this self::B::#redir(x, #context)
+    ;
+  constructor #redir(self::X x, final Vector #context) → void
+    : dynamic #t1 = #context[1] = x, self::B::x = #context[1], super core::Object::•() {
+    final () → dynamic fn = MakeClosure<() → dynamic>(self::closure#B#function#fn, #context);
+    fn.call();
+  }
+}
 static method main() → dynamic {
   self::A a = new self::A::•(new self::X::•());
+  self::B b = new self::B::•(new self::X::•());
+}
+static method closure#B#function#fn(Vector #contextParameter) → dynamic {
+  core::print(#contextParameter[1]);
 }