Remove all vestiges of memcache

Memcache is already off but now it's not in the code anymore.

This includes removing domain creation failfast, since that is actually
slower now than just running the flow - all you gain is a non-transactional
read over a transactional read, but the cost is that you always pay that
read, which is going to drive up latency.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=158183506

java/google/registry/tools/server/KillAllEppResourcesAction.java

@@ -22,7 +22,6 @@ import static google.registry.util.PipelineUtils.createJobPath;
 import com.google.appengine.tools.mapreduce.Mapper;
 import com.google.common.collect.ImmutableList;
 import com.googlecode.objectify.Key;
-import com.googlecode.objectify.Work;
 import google.registry.config.RegistryEnvironment;
 import google.registry.mapreduce.MapreduceRunner;
 import google.registry.mapreduce.inputs.EppResourceInputs;
@@ -92,14 +91,7 @@ public class KillAllEppResourcesAction implements Runnable {
       for (Key<Object> key : ofy().load().ancestor(resourceKey).keys()) {
         emitAndIncrementCounter(resourceKey, key);
       }
-      // Load in a transaction to make sure we don't get stale data (in case of host renames).
-      // TODO(b/27424173): A transaction is overkill. When we have memcache-skipping, use that.
-      EppResource resource = ofy().transactNewReadOnly(
-          new Work<EppResource>() {
-            @Override
-            public EppResource run() {
-              return ofy().load().key(eri.getKey()).now();
-            }});
+      EppResource resource = ofy().load().key(eri.getKey()).now();
       // TODO(b/28247733): What about FKI's for renamed hosts?
       Key<?> indexKey = resource instanceof DomainApplication
           ? DomainApplicationIndex.createKey((DomainApplication) resource)