Delete polymorphicJacksonSerialization artifacts on exit

Author: diastremskii

modules/openapi-generator/src/test/java/org/openapitools/codegen/kotlin/KotlinClientCodegenModelTest.java

@@ -573,7 +573,7 @@ public void polymorphicKotlinxSerialization() throws IOException {
     @Test(description = "generate polymorphic jackson model")
     public void polymorphicJacksonSerialization() throws IOException {
         File output = Files.createTempDirectory("test").toFile();
-//        output.deleteOnExit();
+        output.deleteOnExit();
 
         final CodegenConfigurator configurator = new CodegenConfigurator()
                 .setGeneratorName("kotlin")