add test files

js/js.translator/testFiles/webDemoExamples1/cases/patternMatching.kt

@@ -0,0 +1,18 @@
+fun main(args : Array<String>) {
+    cases("Hello")
+    cases(1)
+    cases(MyClass())
+    cases("hello")
+}
+
+fun cases(obj : Any) {
+  when(obj) {
+    1          -> println("One")
+    "Hello"    -> println("Greeting")
+    !is String -> println("Not a string")
+    else       -> println("Unknown")
+  }
+}
+
+class MyClass() {
+}