[IR] Remove IrExtensionGenerator

compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/extensions/IrGenerationExtension.kt

@@ -18,7 +18,6 @@ import org.jetbrains.kotlin.ir.declarations.IrModuleFragment
 import org.jetbrains.kotlin.ir.descriptors.IrBuiltIns
 import org.jetbrains.kotlin.ir.symbols.*
 import org.jetbrains.kotlin.ir.util.IrDeserializer
-import org.jetbrains.kotlin.ir.util.IrExtensionGenerator
 import org.jetbrains.kotlin.ir.util.ReferenceSymbolTable
 import org.jetbrains.kotlin.ir.util.TypeTranslator
 import org.jetbrains.kotlin.name.FqName
@@ -108,7 +107,7 @@ open class IrPluginContext(
     }
 }
 
-interface IrGenerationExtension : IrExtensionGenerator {
+interface IrGenerationExtension {
     companion object :
         ProjectExtensionDescriptor<IrGenerationExtension>("org.jetbrains.kotlin.irGenerationExtension", IrGenerationExtension::class.java)
 

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/util/SymbolTable.kt

@@ -47,10 +47,6 @@ interface LazyIrProvider : IrProvider {
     override fun getDeclaration(symbol: IrSymbol): IrLazyDeclarationBase?
 }
 
-interface IrExtensionGenerator {
-    fun declare(symbol: IrSymbol): IrDeclaration? = null
-}
-
 interface IrDeserializer : IrProvider {
     fun init(moduleFragment: IrModuleFragment?) {}
 }