JS: move expressions test to box tests

js/js.translator/testData/box/expression/function/functionLiteral.kt

@@ -0,0 +1,9 @@
+package foo
+
+fun box(): String {
+    var sum = 0
+    val addFive = { a: Int -> a + 5 }
+    sum = addFive(sum)
+    if (sum != 5) return "fail: $sum"
+    return "OK"
+}