AbstractDaemonTest: Use exactRef instead of getRefs

Change-Id: I4468985c6cce39c31da8bf4ae043f9cc18f056d1
diff --git a/java/com/google/gerrit/acceptance/AbstractDaemonTest.java b/java/com/google/gerrit/acceptance/AbstractDaemonTest.java
index 0e62938..3c8f170 100644
--- a/java/com/google/gerrit/acceptance/AbstractDaemonTest.java
+++ b/java/com/google/gerrit/acceptance/AbstractDaemonTest.java
@@ -14,7 +14,6 @@
 
 package com.google.gerrit.acceptance;
 
-import static com.google.common.collect.ImmutableMap.toImmutableMap;
 import static com.google.common.truth.Truth.assertThat;
 import static com.google.common.truth.Truth.assert_;
 import static com.google.common.truth.Truth8.assertThat;
@@ -1209,13 +1208,6 @@
       throws Exception {
     TestRepository<?> localRepo = cloneProject(proj);
     GitUtil.fetch(localRepo, "refs/*:refs/*");
-    ImmutableMap<String, Ref> refs =
-        localRepo
-            .getRepository()
-            .getRefDatabase()
-            .getRefs()
-            .stream()
-            .collect(toImmutableMap(Ref::getName, r -> r));
     Map<Branch.NameKey, RevTree> refValues = new HashMap<>();
 
     for (Branch.NameKey b : trees.keySet()) {
@@ -1223,7 +1215,7 @@
         continue;
       }
 
-      Ref r = refs.get(b.get());
+      Ref r = localRepo.getRepository().exactRef(b.get());
       assertThat(r).isNotNull();
       RevWalk rw = localRepo.getRevWalk();
       RevCommit c = rw.parseCommit(r.getObjectId());