JS: move expressions test to box tests

js/js.translator/testData/box/expression/equals/arrays.kt

@@ -0,0 +1,13 @@
+package foo
+
+fun box(): String {
+    val a = arrayOf(1, 2, 3)
+    val b = arrayOf(1, 2, 3)
+    val c = a
+
+    if (a == b) return "fail1"
+    if (a != c) return "fail2"
+    if (c == b) return "fail3"
+
+    return "OK"
+}