Migrate boxWithJava tests to multi-file framework

compiler/testData/codegen/boxWithJava/reflection/callPrivateJavaMethod.kt

@@ -0,0 +1,36 @@
+// FILE: J.java
+
+public class J {
+    private final String result;
+
+    private J(String result) {
+        this.result = result;
+    }
+
+    private String getResult() {
+        return result;
+    }
+}
+
+// FILE: K.kt
+
+import kotlin.reflect.*
+import kotlin.reflect.jvm.*
+import kotlin.test.*
+
+fun box(): String {
+    val c = J::class.constructors.single()
+    assertFalse(c.isAccessible)
+    assertFailsWith(IllegalCallableAccessException::class) { c.call("") }
+
+    c.isAccessible = true
+    assertTrue(c.isAccessible)
+    val j = c.call("OK")
+
+    val m = J::class.members.single { it.name == "getResult" }
+    assertFalse(m.isAccessible)
+    assertFailsWith(IllegalCallableAccessException::class) { m.call(j)!! }
+
+    m.isAccessible = true
+    return m.call(j) as String
+}