[FIR] Replace inheritance with delegation for FirProvider and FirSymbolProvider

compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/backend/Fir2IrDeclarationStorage.kt

@@ -748,7 +748,7 @@ class Fir2IrDeclarationStorage(
     }
 
     private fun getFirClassByFqName(classId: ClassId): FirClass<*>? {
-        val declaration = firProvider.getClassLikeSymbolByFqName(classId) ?: firSymbolProvider.getClassLikeSymbolByFqName(classId)
+        val declaration = firSymbolProvider.getClassLikeSymbolByFqName(classId)
         return declaration?.fir as? FirClass<*>
     }
 
@@ -1063,4 +1063,4 @@ class Fir2IrDeclarationStorage(
             Name.identifier("valueOf") to IrSyntheticBodyKind.ENUM_VALUEOF
         )
     }
-}
+}