Merge boxWithStdlib testData into box, delete BoxWithStdlib test

compiler/testData/codegen/box/reflection/enclosing/lambdaInMemberFunctionInNestedClass.kt

@@ -0,0 +1,23 @@
+// WITH_REFLECT
+
+class C {
+    class D {
+        fun foo(): Any {
+            return {}
+        }
+    }
+}
+
+fun box(): String {
+    val javaClass = C.D().foo().javaClass
+    val enclosingMethod = javaClass.getEnclosingMethod()
+    if (enclosingMethod?.getName() != "foo") return "method: $enclosingMethod"
+
+    val enclosingClass = javaClass.getEnclosingClass()
+    if (enclosingClass?.getSimpleName() != "D") return "enclosing class: $enclosingClass"
+
+    val declaringClass = javaClass.getDeclaringClass()
+    if (declaringClass != null) return "anonymous function has a declaring class: $declaringClass"
+
+    return "OK"
+}