This reverts commit d84f908641.
Reason for revert: Causing internal failures.
Original change's description:
> [ddc] Update DDC compiler to start using the new async transform.
>
> Updates compiler.dart to use the new async transformation.
>
> Some key things to note:
> - Dart Let and BlockExpression expressions are represented as IIFEs in DDC compiled code. For non-async code this works fine but this doesn't work when they contain "await" expressions. When these expressions contain awaits we use the same lowering as we would for an async function, but instead apply it to the IIFE function. Then we simply await the IIFE Call expression as the IIFE will return a future after the transform.
> - For async/sync*/async* functions we want to make sure parameter initialization happens synchronously before any of the async logic is hit. To do this we first apply the async transform the user-code function body. We then prepend the paramter initialization logic to the body of the transformed function.
> - We add support for JS_RAW_EXCEPTION which allows the machinery in async_patch to access the wrapped JS exception in a catch block rather than the unwrapped Dart exception.
> - Stacktraces and sourcemaps have some differences. There is still room for improvement in these but they should at least allow users to reasonably step through parts of the async code.
>
>
> There are also several test fixes/updates associated with this change. The test_runner wrapper no longer has to inject in asyncStart/asyncEnd calls, these are handled by the new async logic.
>
> Change-Id: I0f9f547cd9eb52ff7d850d277876d4d57568a14e
> Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/374444
> Reviewed-by: Bob Nystrom <rnystrom@google.com>
> Reviewed-by: Mark Zhou <markzipan@google.com>
> Reviewed-by: Johnni Winther <johnniwinther@google.com>
> Reviewed-by: Nicholas Shahan <nshahan@google.com>
Change-Id: Ia939fe5a9dfd3a5031b06a7ea26c52e58b89f011
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/375701
Reviewed-by: Bob Nystrom <rnystrom@google.com>
Reviewed-by: Jake Macdonald <jakemac@google.com>
Commit-Queue: Nate Biggs <natebiggs@google.com>
Reviewed-by: Johnni Winther <johnniwinther@google.com>
Reviewed-by: Mark Zhou <markzipan@google.com>
Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Reviewed-by: Nicholas Shahan <nshahan@google.com>
Nate Biggs
1812619b20