Checks: Introduce check blocks into the terraform node and transform graph

[liamcervante]

This PR adds Transform and Node structures into the Terraform processing graph, ensuring that Check blocks are processed with the rest of the Terraform configuration.

It outputs the Check results into diagnostics and the plan file, using the same mechanism through which existing CheckRule blocks are exposed. CheckRules from within Check blocks do, however, only ever expose warning diagnostics instead of error diagnostics.

CheckRules within Check blocks are also not exported to the state files, as they execute on every execution of a plan or apply anyway.

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This PR is part of chain of PRs introducing the new Checks feature into Terraform for v1.5. The chain of PRs is as follows:

Branch	Description	Pull Request
liamcervante/checks/scoped	Add support for scoped resources.	#32732
liamcervante/checks/addr	Add Terraform addresses for new Check blocks.	#32733
liamcervante/checks/configs	Add config parsing new Check blocks.	#32734
liamcervante/checks/graph	Add nodes and transforms for processing new Check blocks.	#32735

I have created the chain to make reviewing the smaller contained part of the process easier. IF you want to view all the changes together in a single PR, navigate to the last PR in the chain and compare it to the main branch and you will see all changes from all prior PRs in a single place.

[jbardin]

Do checks need to run during destroy? This isn't going to work currently, because modules are not expanded during destroy, so nested check blocks will panic with no expansion has been registered for module.name. They also are not linked up in the destroy graph to anything since the normal resource nodes don't exist, and may fail to read any data they are validating.

I think what we want here is just to skip the check blocks entirely for any full destroy operation.

[liamcervante]

I think what we want here is just to skip the check blocks entirely for any full destroy operation.

Done!

[jbardin]

Because having nodes in the graph at all can change how the destroy graph is constructed (i.e. these are currently still going to run into problems when placed in an expanding module) , I think it's better to exclude the nodes entirely whenever possible.

[liamcervante]

Okay, done much more strongly now!

[github-actions]

Reminder for the merging maintainer: if this is a user-visible change, please update the changelog on the appropriate release branch.

[github-actions]

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