of the class used in @UseSerializers: Use methods to receive
full list of supertypes.
K1 supertypes() call returned all supertypes, while
IrClass.supertypes and FirClassSymbol.resolvedSuperTypes return only immediate ones.
This lead to a difference in behavior between K1 and K2, and regression
after plugin backend was rewritten from descriptors to IR.
#KT-55340 Fixed
Leonid Startsev