[Test] Move KotlinAgainstKotlin tests under BlackBoxCodegen tests

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

@@ -0,0 +1,21 @@
+// MODULE: lib
+// FILE: A.kt
+
+package library
+
+public enum class EnumClass {
+    ENTRY;
+
+    public companion object {
+        public fun entry(): EnumClass = ENTRY
+    }
+}
+
+// MODULE: main(lib)
+// FILE: B.kt
+
+import library.EnumClass
+
+fun box(): String {
+    return if (EnumClass.entry() != EnumClass.ENTRY) "Fail" else "OK"
+}