[K/JS] Add ES6 typescript tests + fix a few bugs for it

js/js.tests/test/org/jetbrains/kotlin/generators/tests/GenerateJsTests.kt

@@ -130,6 +130,10 @@ fun main(args: Array<String>) {
                 model("typescript-export/", pattern = "^([^_](.+))\\.kt$")
             }
 
+            testClass<AbstractIrJsES6TypeScriptExportTest> {
+                model("typescript-export/", pattern = "^([^_](.+))\\.kt$")
+            }
+
             testClass<AbstractJsIrLineNumberTest> {
                 model("lineNumbers/")
             }

js/js.tests/test/org/jetbrains/kotlin/js/test/ir/AbstractJsIrTest.kt

@@ -107,6 +107,16 @@ open class AbstractIrJsTypeScriptExportTest : AbstractJsIrTest(
     }
 }
 
+open class AbstractIrJsES6TypeScriptExportTest : AbstractJsIrES6Test(
+    pathToTestDir = "${JsEnvironmentConfigurator.TEST_DATA_DIR_PATH}/typescript-export/",
+    testGroupOutputDirPrefix = "es6-typescript-export/"
+) {
+    override fun configure(builder: TestConfigurationBuilder) {
+        super.configure(builder)
+        configureIrJsTypeScriptExportTest(builder)
+    }
+}
+
 private fun configureIrJsTypeScriptExportTest(builder: TestConfigurationBuilder) {
     with(builder) {
         defaultDirectives {