Support LDAP with anonymous bind disabled

For many users, enabling anonymous bind is not an option from security
perspective.

Test coverage is provided by disabling anonymous bind in the LDAP server
used in product tests --
trinodb/docker-images@4fc1925

presto-password-authenticators/src/main/java/io/prestosql/plugin/password/LdapAuthenticator.java

@@ -76,7 +76,6 @@ public LdapAuthenticator(LdapConfig serverConfig)
                 .put(INITIAL_CONTEXT_FACTORY, "com.sun.jndi.ldap.LdapCtxFactory")
                 .put(PROVIDER_URL, ldapUrl)
                 .build();
-        checkEnvironment(environment);
         this.basicEnvironment = environment;
         this.authenticationCache = CacheBuilder.newBuilder()
                 .expireAfterWrite(serverConfig.getLdapCacheTtl().toMillis(), MILLISECONDS)
@@ -175,16 +174,6 @@ private static String replaceUser(String pattern, String user)
         return pattern.replaceAll("\\$\\{USER}", user);
     }
 
-    private static void checkEnvironment(Map<String, String> environment)
-    {
-        try {
-            closeContext(createDirContext(environment));
-        }
-        catch (NamingException e) {
-            throw new RuntimeException(e);
-        }
-    }
-
     private static void closeContext(DirContext context)
     {
         try {