They appeared, after the changes in previous commits at
org.jetbrains.kotlin.fir.resolve.transformers.body.resolve.FirExpressionsResolveTransformer#transformDelegatedConstructorCall
The idea is that dispatch receiver is available there in old FE, but additional
diagnostic should be reported on it (see KT-38813)
This change was not made intentionaly but it was the easiest way to
support new tower data elements structure and on the other side it's the
correct behavior as for old FE.
Also, if we once would prefer the previous behavior it's still not very
hard to support it