"default transform" for executors

[riccardofelluga]

🚀 Feature

In the discussion for the new trasnformerengine executor #1908 @IvanYashchuk suggested it might be a good idea to add a property to the executor that lists the transforms that are necessary for that executor to create a correct trace. I am opening this issue to track that effort as I want to implement it as a separate PR because it touches the transform for execution function

cc @mruberry

[t-vi]

I'm glad you bring this up! Let's do a technical session on this.

As a preview, my thoughts here are that we should make a connection, but a different one:

• To my mind, we should focus on transforms and have them come with an executor. The Transform is the more powerful/general concept and if a transform happens to need custom symbols, it needs an executor. The interesting thing will be how to order executors (explicitly given, from transforms, default / always on).

• We could even go so far to eliminate executors as a thing the use interfaces (so executors would always be given in terms of transforms).

• The trouble with default anything is that it does not take parameters. We see this with executors, my feeling is that about half the JIT options I dislike should be executor options.