Use transaction time for deletion time cache ticker (#2848)

Basically, what happened is that the cache's expireAfterWrite was being
called some number of milliseconds (say, 50-100) after the transaction
was started. That method used the transaction time instead of the
current time, so as a result the entries were sticking around 50-100ms
longer in the cache than they should have been.

This fix contains two parts, each of which I believe would be sufficient
on their own to fix the issue:
1. Use the currentTime passed in in Expiry::expireAfterCreate
2. Use the transaction time in the cache's Ticker. This keeps everything
   on the same schedule.

core/src/test/java/google/registry/flows/domain/DomainDeletionTimeCacheTest.java

@@ -26,6 +26,7 @@ import google.registry.testing.DatabaseHelper;
 import google.registry.testing.FakeClock;
 import java.util.Optional;
 import org.joda.time.DateTime;
+import org.joda.time.Duration;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.extension.RegisterExtension;
@@ -67,7 +68,8 @@ public class DomainDeletionTimeCacheTest {
     Domain domain = persistActiveDomain("domain.tld");
     assertThat(getDeletionTimeFromCache("domain.tld")).hasValue(END_OF_TIME);
     persistDomainAsDeleted(domain, clock.nowUtc().plusDays(1));
-    // Without intervention, the cache should have the old data
+    // Without intervention, the cache should have the old data, even if a few minutes have passed
+    clock.advanceBy(Duration.standardMinutes(5));
     assertThat(getDeletionTimeFromCache("domain.tld")).hasValue(END_OF_TIME);
   }
 
@@ -79,6 +81,16 @@ public class DomainDeletionTimeCacheTest {
     assertThat(getDeletionTimeFromCache("domain.tld")).hasValue(clock.nowUtc().plusDays(1));
   }
 
+  @Test
+  void testCache_expires() {
+    Domain domain = persistActiveDomain("domain.tld");
+    assertThat(getDeletionTimeFromCache("domain.tld")).hasValue(END_OF_TIME);
+    DateTime elevenMinutesFromNow = clock.nowUtc().plusMinutes(11);
+    persistDomainAsDeleted(domain, elevenMinutesFromNow);
+    clock.advanceBy(Duration.standardMinutes(30));
+    assertThat(getDeletionTimeFromCache("domain.tld")).hasValue(elevenMinutesFromNow);
+  }
+
   private Optional<DateTime> getDeletionTimeFromCache(String domainName) {
     return tm().transact(() -> cache.getDeletionTimeForDomain(domainName));
   }