424e670576
This is a reland of 553bfea531
Original change's description:
> Mark AstTestFactory as internal.
>
> I want to continue disallowing users to create AST nodes.
>
> Change-Id: I6597fcf4fbb767cde35320e3b8777873faf5c5bd
> Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/194600
> Reviewed-by: Samuel Rawlins <srawlins@google.com>
> Commit-Queue: Konstantin Shcheglov <scheglov@google.com>
Change-Id: I097fc5f665880666829eeb982f7fa3b450bb203e
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/194681
Reviewed-by: Ivan Inozemtsev <iinozemtsev@google.com>
Commit-Queue: Ivan Inozemtsev <iinozemtsev@google.com>