Merge boxWithStdlib testData into box, delete BoxWithStdlib test

compiler/testData/codegen/box/reflection/call/privateProperty.kt

@@ -0,0 +1,19 @@
+// WITH_REFLECT
+
+import kotlin.reflect.*
+import kotlin.reflect.jvm.*
+import kotlin.test.*
+
+class A(private var result: String)
+
+fun box(): String {
+    val a = A("abc")
+
+    val p = A::class.declaredMemberProperties.single() as KMutableProperty1<A, String>
+    p.isAccessible = true
+    assertEquals("abc", p.call(a))
+    assertEquals(Unit, p.setter.call(a, "def"))
+    assertEquals("def", p.getter.call(a))
+
+    return "OK"
+}