[Test] Properly merge box against java testdata into codegen/box

Previous commit about it was 3199ce03 and it was completely wrong

compiler/testData/codegen/box/staticFun/classWithNestedEnum.kt

@@ -0,0 +1,20 @@
+// DONT_TARGET_EXACT_BACKEND: JS JS_IR JS_IR_ES6 WASM NATIVE
+// MODULE: lib
+// FILE: test/JavaClass.java
+
+package test;
+
+public class JavaClass {
+    public enum E { ENTRY }
+    
+    public static String foo() { return "OK"; }
+}
+
+// MODULE: main(lib)
+// FILE: 1.kt
+
+package test
+
+fun box(): String {
+    return JavaClass.foo()!!
+}