JS: move expressions test to box tests

js/js.translator/testData/box/expression/invoke/invokeWithExtensionReceiver.kt

@@ -0,0 +1,8 @@
+package foo
+
+operator fun Int.invoke(x: Int) = this + x
+fun box(): String {
+    val result = 1(2)
+    if (result != 3) return "fail: $result"
+    return "OK"
+}