Make the superuser flag bypass TLD access checks

The --superuser command in the nomulus command-line tool should be
bypassing checks on whether the passed-in registrar client ID has access
to the TLD in question, but currently it is not.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=158974462

javatests/google/registry/flows/domain/DomainTransferRequestFlowTest.java

@@ -571,6 +571,19 @@ public class DomainTransferRequestFlowTest
     doSuccessfulTest("domain_transfer_request.xml", "domain_transfer_request_response.xml");
   }
 
+  @Test
+  public void testSuccess_superuserNotAuthorizedForTld() throws Exception {
+    setupDomain("example", "tld");
+    persistResource(
+        Registrar.loadByClientId("NewRegistrar")
+            .asBuilder()
+            .setAllowedTlds(ImmutableSet.<String>of())
+            .build());
+    clock.advanceOneMilli();
+    // We don't verify the results; just check that the flow doesn't fail.
+    runTest("domain_transfer_request.xml", UserPrivileges.SUPERUSER);
+  }
+
   @Test
   public void testSuccess_autorenewGraceActive_onlyAtTransferRequestTime() throws Exception {
     setupDomain("example", "tld");