Consolidate wildcarded domain_create testdata XMLs

It's simpler to have fewer of these, and it's clearer from callsites if it's
always explicit exactly which domain is being created.

I also removed two irregularities: domain_create.xml included hostnames but
domain_create_wildcard.xml did not, and the former called the domain name
%DOMAIN% whereas the latter called it %HOSTNAME%.

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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=204956433

javatests/google/registry/flows/EppCommitLogsTest.java

@@ -101,7 +101,7 @@ public class EppCommitLogsTest extends ShardableTestCase {
     clock.advanceBy(standardDays(1));
     DateTime timeAtCreate = clock.nowUtc();
     clock.setTo(timeAtCreate);
-    eppLoader = new EppLoader(this, "domain_create.xml");
+    eppLoader = new EppLoader(this, "domain_create.xml", ImmutableMap.of("DOMAIN", "example.tld"));
     runFlow();
     ofy().clearSessionCache();
     Key<DomainResource> key = Key.create(ofy().load().type(DomainResource.class).first().now());