[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/functions/max.kt

@@ -0,0 +1,18 @@
+// DONT_TARGET_EXACT_BACKEND: JS JS_IR JS_IR_ES6 WASM NATIVE
+// MODULE: lib
+// FILE: Foo.java
+
+import java.util.*;
+
+public class Foo {
+    public static <T extends Object & Comparable<? super T>> T max(Collection<? extends T> coll) {
+        return Collections.max(coll);
+    }
+}
+
+// MODULE: main(lib)
+// FILE: 1.kt
+
+fun box(): String {
+    return Foo.max(java.util.Arrays.asList("AK", "OK", "EK"))!!
+}