KT-12877: reorganize JS module tests to support different module systems. Test JsModule in conjunction with JsNonModule and plain module type

js/js.translator/testData/box/jsModule/externalFunctionPlain.kt

@@ -0,0 +1,10 @@
+package foo
+
+@JsModule("lib")
+@JsNonModule
+@native fun foo(y: Int): Int = noImpl
+
+fun box(): String {
+    assertEquals(65, foo(42))
+    return "OK"
+}