KT-2752: add basic tests for JsName

js/js.translator/testData/box/jsName/overridenFromInterface.kt

@@ -0,0 +1,20 @@
+package foo
+
+interface A {
+    @JsName("js_f") fun f(x: Int): String
+}
+
+class B : A {
+    override fun f(x: Int) = "B.f($x)"
+}
+
+fun test() = js("""
+var module = Kotlin.modules.JS_TESTS.foo;
+return new (module.B)().js_f(23);
+""")
+
+fun box(): String {
+    val result = test()
+    assertEquals("B.f(23)", result);
+    return "OK"
+}