KJS: introduce $kotlin_test_internal$ to expose some helper functions in the tests

js/js.translator/testData/box/jsModule/importCountCommonJS.js

@@ -1,4 +1,4 @@
-__beginModule__();
+$kotlin_test_internal$.beginModule();
 module.exports = function(param) {
     switch (typeof param) {
         case "number":
@@ -9,4 +9,4 @@ module.exports = function(param) {
             return "c";
     }
 };
-__endModule__("lib");
+$kotlin_test_internal$.endModule("lib");

js/js.translator/testData/moduleEmulation.js

@@ -2,18 +2,22 @@
 var emulatedModules = { kotlin: kotlin };
 var module = { exports: {} };
 
+// TODO don't expose by default when run test with AMD module kind
 function require(moduleId) {
     return emulatedModules[moduleId];
 }
 
-function __beginModule__() {
-    module.exports = {};
-}
-
-function __endModule__(moduleId) {
-    emulatedModules[moduleId] = module.exports;
-}
+var $kotlin_test_internal$ = {
+    require: require,
+    beginModule : function () {
+        module.exports = {};
+    },
+    endModule : function(moduleId) {
+        emulatedModules[moduleId] = module.exports;
+    }
+};
 
+// TODO expose only when run test with AMD or UMD module kind
 function define(moduleId, dependencies, body) {
     var resolvedDependencies = [];
     emulatedModules[moduleId] = {};