Supported propagation for Java subclass of Kotlin class.

compiler/testData/loadJavaCustom/subclassingKotlinInJava/expected.txt

@@ -0,0 +1,10 @@
+namespace test
+
+public open class test.JavaSubclass : test.KotlinClass {
+    public final /*constructor*/ fun <init>(): test.JavaSubclass
+    public open override /*1*/ fun foo(): jet.String
+}
+public open class test.KotlinClass : jet.Any {
+    public final /*constructor*/ fun <init>(): test.KotlinClass
+    public open fun foo(): jet.String
+}

compiler/testData/loadJavaCustom/subclassingKotlinInJava/java/test/JavaSubclass.java

@@ -0,0 +1,7 @@
+package test;
+
+public class JavaSubclass extends KotlinClass {
+    public String foo() {
+        return "";
+    }
+}

compiler/testData/loadJavaCustom/subclassingKotlinInJava/kotlin/KotlinClass.kt

@@ -0,0 +1,5 @@
+package test
+
+public open class KotlinClass {
+    public open fun foo(): String = ""
+}