Refactor out creation of server TRIDs so they can be tested

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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=152837185

javatests/google/registry/model/reporting/HistoryEntryTest.java

@@ -44,7 +44,7 @@ public class HistoryEntryTest extends EntityTestCase {
       .setModificationTime(clock.nowUtc())
       .setClientId("foo")
       .setOtherClientId("otherClient")
-      .setTrid(Trid.create("ABC-123"))
+      .setTrid(Trid.create("ABC-123", "server-trid"))
       .setBySuperuser(false)
       .setReason("reason")
       .setRequestedByRegistrar(false)