Remove code supporting incremental compilation in dart2js

pkg/compiler/lib/src/apiimpl.dart

Index: pkg/compiler/lib/src/apiimpl.dart
diff --git a/pkg/compiler/lib/src/apiimpl.dart b/pkg/compiler/lib/src/apiimpl.dart
index 2861f6b8fe352731fd64603ca007ef67ccb48548..d569bcdba7c004d9fd00336ebeaad3548362705d 100644
--- a/pkg/compiler/lib/src/apiimpl.dart
+++ b/pkg/compiler/lib/src/apiimpl.dart
@@ -226,6 +226,7 @@ class CompilerImpl extends Compiler {
         });
       });
     }
+    // TODO(johnniwinther): This does not apply anymore.
     // The incremental compiler sets up the sdk before run.
     // Therefore this will be called a second time.
     return future;