TEST: Fix Engine#testRebuildLocalCheckpointTracker

In this test, we verify that the LocalCheckpointTracker is initialized
with the operations of the safe commit. And the test fails because
Engine#Index does not implement the equals method (should not
implement as it consists of a mutable ParsedDocument).

Closes #36470

server/src/test/java/org/elasticsearch/index/engine/InternalEngineTests.java

@@ -5419,7 +5419,6 @@ public class InternalEngineTests extends EngineTestCase {
         }
     }
 
-    @AwaitsFix(bugUrl = "https://github.com/elastic/elasticsearch/issues/36470")
     public void testRebuildLocalCheckpointTracker() throws Exception {
         Settings.Builder settings = Settings.builder()
             .put(defaultSettings.getSettings())
@@ -5453,19 +5452,20 @@ public class InternalEngineTests extends EngineTestCase {
                 docs = getDocIds(engine, true);
             }
             trimUnsafeCommits(config);
-            List<Engine.Operation> safeCommit = null;
+            Set<Long> seqNosInSafeCommit = null;
             for (int i = commits.size() - 1; i >= 0; i--) {
                 if (commits.get(i).stream().allMatch(op -> op.seqNo() <= globalCheckpoint.get())) {
-                    safeCommit = commits.get(i);
+                    seqNosInSafeCommit = commits.get(i).stream().map(Engine.Operation::seqNo).collect(Collectors.toSet());
                     break;
                 }
             }
-            assertThat(safeCommit, notNullValue());
+            assertThat(seqNosInSafeCommit, notNullValue());
             try (InternalEngine engine = new InternalEngine(config)) { // do not recover from translog
                 final LocalCheckpointTracker tracker = engine.getLocalCheckpointTracker();
                 for (Engine.Operation op : operations) {
-                    assertThat("seq_no=" + op.seqNo() + " max_seq_no=" + tracker.getMaxSeqNo() +
-                            " checkpoint=" + tracker.getCheckpoint(), tracker.contains(op.seqNo()), equalTo(safeCommit.contains(op)));
+                    assertThat(
+                        "seq_no=" + op.seqNo() + " max_seq_no=" + tracker.getMaxSeqNo() + "checkpoint=" + tracker.getCheckpoint(),
+                        tracker.contains(op.seqNo()), equalTo(seqNosInSafeCommit.contains(op.seqNo())));
                 }
                 engine.initializeMaxSeqNoOfUpdatesOrDeletes();
                 engine.recoverFromTranslog(translogHandler, Long.MAX_VALUE);