Added switch (enum-only when) lowering

Added enum ordinal to serialization

backend.native/tests/serialization/enum_ordinal/library.kt

@@ -0,0 +1,9 @@
+enum class Color {
+    RED, GREEN, BLUE, CYAN, MAGENTA, YELLOW
+}
+
+fun determineColor(code: Int): Color = when (code) {
+    0 -> Color.BLUE
+    1 -> Color.MAGENTA
+    else -> Color.CYAN
+}

backend.native/tests/serialization/enum_ordinal/main.kt

@@ -0,0 +1,14 @@
+fun main(args: Array<String>) {
+    println(Color.RED.ordinal)
+    println(Color.GREEN.ordinal)
+    println(Color.BLUE.ordinal)
+    val color = when (determineColor(args.size)) {
+        Color.RED -> println("r")
+        Color.GREEN -> println("g")
+        Color.BLUE -> println("b")
+        Color.CYAN -> println("c")
+        Color.MAGENTA -> println("m")
+        Color.YELLOW -> println("y")
+
+    }
+}