Revert generate pipeline plugin

[DougGregor]

Revert #416 and #419 because they appear to be breaking Swift pull request testing.

[DougGregor]

@swift-ci please test

[DougGregor]

@allevato this revert PR is because we think #416 and #419 are causing the silent SwiftSyntax build failures we're seeing in Swift CI. The referenced PR (swiftlang/swift#61545) is where we're testing out this theory.

[allevato]

@ahoppen mentioned this to me as well. Given the issue on Windows as well (#422) maybe this is the best option if we confirm that it's the problem.

Any idea why the plug-in is causing the failures?

If we had the swift-ci trigger working on this repo, would it have caught the problem before it was merged? cc @shahmishal

[allevato]

I'll go ahead and approve this just in case; feel free to merge it if your testing confirms the plugin was the problem, and let me know if there's anything I can do to help get it working again after that!

[DougGregor]

Yeah, I've confirmed that the plug-in was the problem, so I'm going to go ahead and merge. Sorry about that--let's look for a path forward, because this is a nice cleanup and it's unfortunate we have to revert.

[ahoppen]

If we had the swift-ci trigger working on this repo, would it have caught the problem before it was merged? cc @shahmishal

I think what you can do in the meantime while CI triggers are not set up for this repo, is to create a fake PR to https://github.com/apple/swift/, mention the swift-format PR you want to test and add @swift-ci Please test (or your favorite test invocation). I am often doing this in swiftlang/swift#37710.