Although I don't plan to bring over new assertions wholesale
into the current qualification branch, it's entirely possible
that various minor changes in main will use the new assertions;
having this basic support in the release branch will simplify that.
(This is why I'm adding the includes as a separate pass from
rewriting the individual assertions)
When there are problems in the properties in the target type, witness
methods may not be synthesized. Don't try to add such methods.
https://github.com/apple/swift/issues/72387
* Support extensions including conditional conformance
* Correct access modifiers
* More correct lookup for the synthesized declarations
* Avoid printing decls in nested types (rdar://98025945)
