JS: move RTTI tests to proper location

js/js.translator/testData/box/rtti/rttiForClass.kt

@@ -0,0 +1,31 @@
+package foo
+
+class D
+
+open class A
+
+open class B : A()
+
+open class C : B()
+
+fun box(): String {
+    val a: Any = A()
+    val b: Any = B()
+    val c: Any = C()
+    if (a !is A) return "a !is A"
+
+    val t = a is A
+    if (!t) return "t = a is A; t != true"
+
+    if (b !is A) return "b !is A"
+    if (b !is B) return "b !is B"
+
+    if (c !is A) return "c !is A"
+    if (c !is B) return "c !is B"
+    if (c !is C) return "c !is C"
+
+    if (a is D) return "a is D"
+    if (b is D) return "b is D"
+
+    return "OK"
+}