Move superinterface to the only subclass of FunctionBase

libraries/stdlib/jvm/runtime/kotlin/jvm/internal/FunctionBase.java

@@ -7,8 +7,6 @@ package kotlin.jvm.internal;
 
 import kotlin.Function;
 
-import java.io.Serializable;
-
-public interface FunctionBase extends Function, Serializable {
+public interface FunctionBase extends Function {
     int getArity();
 }

libraries/stdlib/jvm/runtime/kotlin/jvm/internal/Lambda.kt

@@ -5,8 +5,10 @@
 
 package kotlin.jvm.internal
 
-public abstract class Lambda(private val arity: Int) : FunctionBase {
-    override fun getArity() = arity
+import java.io.Serializable
 
-    override fun toString() = Reflection.renderLambdaToString(this)
+abstract class Lambda(private val arity: Int) : FunctionBase, Serializable {
+    override fun getArity(): Int = arity
+
+    override fun toString(): String = Reflection.renderLambdaToString(this)
 }