KT-20421 fixing code generation for the case when "object" extends "class". It should look like: "object: class()".

nj2k/testData/newJ2k/issues/kt-20421.java

@@ -0,0 +1,6 @@
+class Base {
+    static final int F = 0;
+}
+final class A extends Base {
+    static final int F1 = 0;
+}

nj2k/testData/newJ2k/issues/kt-20421.kt

@@ -0,0 +1,9 @@
+internal open class Base {
+    companion object {
+        const val F = 0
+    }
+}
+
+internal object A : Base() {
+    const val F1 = 0
+}