[Test] Move KotlinAgainstKotlin tests under BlackBoxCodegen tests

compiler/testData/codegen/box/compileKotlinAgainstKotlin/nestedEnum.kt

@@ -0,0 +1,21 @@
+// MODULE: lib
+// FILE: A.kt
+
+package aaa
+
+class A {
+    enum class E {
+        A
+    }
+}
+
+// MODULE: main(lib)
+// FILE: B.kt
+
+fun box(): String {
+    val str = aaa.A.E.A
+    if (str.toString() != "A") {
+        return "Fail $str"
+    }
+    return "OK"
+}