Remove inadvertent addition of adding NIO codebase

This arose from a backport. This commit removes it since it does not
make sense in 6.x where NIO does not exist.

Author: jasontedor

test/framework/src/main/java/org/elasticsearch/bootstrap/BootstrapForTesting.java

@@ -1,4 +1,4 @@
-/*
+oi/*
  * Licensed to Elasticsearch under one or more contributor
  * license agreements. See the NOTICE file distributed with
  * this work for additional information regarding copyright
@@ -134,7 +134,6 @@ public class BootstrapForTesting {
                 if (System.getProperty("tests.gradle") == null) {
                     // intellij and eclipse don't package our internal libs, so we need to set the codebases for them manually
                     addClassCodebase(codebases,"plugin-classloader", "org.elasticsearch.plugins.ExtendedPluginsClassLoader");
-                    addClassCodebase(codebases,"elasticsearch-nio", "org.elasticsearch.nio.ChannelFactory");
                     addClassCodebase(codebases, "elasticsearch-secure-sm", "org.elasticsearch.secure_sm.SecureSM");
                 }
                 final Policy testFramework = Security.readPolicy(Bootstrap.class.getResource("test-framework.policy"), codebases);