Refactored tests for switch optimization of When expression

compiler/testData/codegen/boxWithStdlib/when/switchOptimizationMultipleConditions.kt

@@ -0,0 +1,15 @@
+fun foo(x: Int): Int {
+    return when (x) {
+        1, 2, 3 -> 1
+        4, 5, 6 -> 2
+        7, 8, 9 -> 3
+        else -> 4
+    }
+}
+
+fun box(): String {
+    var result = (0..10).map(::foo).makeString()
+
+    if (result != "4, 1, 1, 1, 2, 2, 2, 3, 3, 3, 4") return result
+    return "OK"
+}