Drop generic GenericTaskQueue<T> and DeferrableTask<T> now that they are unused. Rename GenericTaskQueue<Timer> to MainThreadTaskQueue and DeferrableTask<Timer> to MainThreadDeferrableTask as they still have some usage.
Created attachment 430500 [details]
Committed r278426 (238450@main): <https://commits.webkit.org/238450@main>
All reviewed patches have been landed. Closing bug and clearing flags on attachment 430500 [details].