[IR] Implement MFVC basic flattening

#KT-1179

compiler/ir/backend.jvm/codegen/src/org/jetbrains/kotlin/backend/jvm/codegen/AnnotationCodegen.kt

@@ -346,6 +346,7 @@ abstract class AnnotationCodegen(
                 declaration.origin.isSynthetic ->
                     true
                 declaration.origin == JvmLoweredDeclarationOrigin.INLINE_CLASS_GENERATED_IMPL_METHOD ||
+                declaration.origin == JvmLoweredDeclarationOrigin.MULTI_FIELD_VALUE_CLASS_GENERATED_IMPL_METHOD ||
                         declaration.origin == IrDeclarationOrigin.GENERATED_SAM_IMPLEMENTATION ->
                     true
                 else ->

compiler/ir/backend.jvm/codegen/src/org/jetbrains/kotlin/backend/jvm/codegen/ExpressionCodegen.kt

@@ -294,6 +294,7 @@ class ExpressionCodegen(
             (irFunction is IrConstructor && irFunction.parentAsClass.isAnonymousObject) ||
             // TODO: Implement this as a lowering, so that we can more easily exclude generated methods.
             irFunction.origin == JvmLoweredDeclarationOrigin.INLINE_CLASS_GENERATED_IMPL_METHOD ||
+            irFunction.origin == JvmLoweredDeclarationOrigin.MULTI_FIELD_VALUE_CLASS_GENERATED_IMPL_METHOD ||
             // Although these are accessible from Java, the functions they bridge to already have the assertions.
             irFunction.origin == IrDeclarationOrigin.BRIDGE_SPECIAL ||
             irFunction.origin == JvmLoweredDeclarationOrigin.SUPER_INTERFACE_METHOD_BRIDGE ||

compiler/ir/backend.jvm/codegen/src/org/jetbrains/kotlin/backend/jvm/intrinsics/HashCode.kt

@@ -37,9 +37,10 @@ object HashCode : IntrinsicMethod() {
         val target = context.state.target
         when {
             irFunction.origin == JvmLoweredDeclarationOrigin.INLINE_CLASS_GENERATED_IMPL_METHOD ||
+                    irFunction.origin == JvmLoweredDeclarationOrigin.MULTI_FIELD_VALUE_CLASS_GENERATED_IMPL_METHOD ||
                     irFunction.origin == IrDeclarationOrigin.GENERATED_DATA_CLASS_MEMBER ||
                     irFunction.origin == IrDeclarationOrigin.GENERATED_MULTI_FIELD_VALUE_CLASS_MEMBER -> {
-                // TODO generate or lower IR for data class / inline class 'hashCode'?
+                // TODO generate or lower IR for data class / value class 'hashCode'?
                 DescriptorAsmUtil.genHashCode(mv, mv, receiverType, target)
             }
             target >= JvmTarget.JVM_1_8 && AsmUtil.isPrimitive(receiverJvmType) -> {