This MR fixes two independent issues causing build failures when using Kapt in combination with the Kotlin serialization plugin (and, very likely, with other plugins as well):
Kapt applied compiler plugins twice, causing errors similar to the one described in KT-65006
Kapt failed to generate @Metadata annotations for plugin-generated companion objects because the corresponding SLC missed containingFile needed for generation of method and class signatures
Merge-request: KT-MR-13970
Merged-by: Pavel Mikhailovskii <Pavel.Mikhailovskii@jetbrains.com>