Add test for obsolete issue

The issue was fixed in df1595e

 #KT-39630 Fixed

compiler/testData/diagnostics/tests/j+k/sam/kt39630.kt

@@ -0,0 +1,14 @@
+// FIR_IDENTICAL
+
+// FILE: A.java
+
+public class A<T> {
+    public void add(T x) {}
+    public static class B extends A<Runnable> {}
+}
+
+// FILE: test.kt
+
+fun test(x: A.B) {
+    x.add { }
+}

compiler/testData/diagnostics/tests/j+k/sam/kt39630.txt

@@ -0,0 +1,19 @@
+package
+
+public fun test(/*0*/ x: A.B): kotlin.Unit
+
+public open class A</*0*/ T : kotlin.Any!> {
+    public constructor A</*0*/ T : kotlin.Any!>()
+    public open fun add(/*0*/ x: T!): kotlin.Unit
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+    public open class B : A<java.lang.Runnable!> {
+        public constructor B()
+        public open override /*1*/ /*fake_override*/ fun add(/*0*/ x: java.lang.Runnable!): kotlin.Unit
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+}