Implement 'this' calls.

test/kernel/regression/this_invoke.dart

Index: test/kernel/regression/this_invoke.dart
diff --git a/test/kernel/regression/issue_000008.dart b/test/kernel/regression/this_invoke.dart
similarity index 80%
copy from test/kernel/regression/issue_000008.dart
copy to test/kernel/regression/this_invoke.dart
index b9f1f6e480aefc2eb0cbaf399221abf9426bcb71..42b95f74af6e36f75b8b5311ba69d2b676d5a068 100644
--- a/test/kernel/regression/issue_000008.dart
+++ b/test/kernel/regression/this_invoke.dart
@@ -3,10 +3,10 @@
 // BSD-style license that can be found in the LICENSE.md file.
 
 class C {
-  final x;
-  C(this.x);
+  m(x) => this(x);
+  call(x) => 42;
 }
 
 main() {
-  new C(42);
+  print(new C().m(42));
 }