JS: trying to implement integer overflow for increment and decrement

js/js.translator/testData/box/number/intIncDecOverflow.kt

@@ -0,0 +1,24 @@
+package foo
+
+
+fun box(): String {
+    var b: Byte = 0x7F
+    b++
+    if (b.toInt() != -0x80) return "fail1a: $b"
+    b--
+    if (b.toInt() != 0x7F) return "fail1b: $b"
+
+    var s: Short = 0x7FFF
+    s++
+    if (s.toInt() != -0x8000) return "fail2a: $s"
+    s--
+    if (s.toInt() != 0x7FFF) return "fail2b: $s"
+
+    var i: Int = 0x7FFFFFFF
+    i++
+    if (i != -0x80000000) return "fail3a: $i"
+    i--
+    if (i != 0x7FFFFFFF) return "fail3b: $i"
+
+    return "OK"
+}