[Test] Merge box against java tests into codegen black box tests

compiler/testData/codegen/boxAgainstJava/sam/smartCastSamConversion.kt

@@ -1,14 +1,4 @@
-// FILE: test.kt
-fun test(a: Any) {
-    a as (String) -> String
-    J.use(a)
-}
-
-fun box(): String {
-    test({s: String? -> s})
-    return "OK"
-}
-
+// MODULE: lib
 // FILE: JFoo.java
 public interface JFoo<T> {
     T foo(T x);
@@ -20,3 +10,16 @@ public class J {
         jfoo.foo(null);
     }
 }
+
+
+// MODULE: main(lib)
+// FILE: test.kt
+fun test(a: Any) {
+    a as (String) -> String
+    J.use(a)
+}
+
+fun box(): String {
+    test({s: String? -> s})
+    return "OK"
+}