Non-deterministic result when merging an empty KllFloatsSketch with two others

Merging an empty KllFloatsSketch with two KllFloatsSketch, with 1 and 200 "items" respectively, does not always produce the same result

I would have expected the following test scenario to pass:

```
@Test
public void test() throws NoSuchAlgorithmException {

KllFloatsSketch t1 = KllFloatsSketch.newHeapInstance();
t1.update(1f);
byte[] tb1 = t1.toByteArray();

KllFloatsSketch t2 = KllFloatsSketch.newHeapInstance();
for(int i=0; i<200; i++) {
t2.update(1f*i);
}
byte[] tb2 = t2.toByteArray();

HashSet digests = new HashSet<>();
for(int i=0; i<30; i++) {
KllFloatsSketch start = KllFloatsSketch.newHeapInstance();

byte[] h1 = Arrays.copyOf(tb1, tb1.length);
byte[] h2 = Arrays.copyOf(tb2, tb2.length);

KllFloatsSketch kll1 = KllFloatsSketch.heapify(MemorySegment.ofArray(h1));
start.merge(kll1);

KllFloatsSketch kll2 = KllFloatsSketch.heapify(MemorySegment.ofArray(h2));
start.merge(kll2);

MessageDigest md5 = MessageDigest.getInstance("MD5");

BigInteger digest = new BigInteger(md5.digest(start.toByteArray()));
digests.add(digest);
System.out.println(digest);
}
assertEquals(1, digests.size());
}
```

The digests are:
```
115710133967357289505160160937439690295
-100233422360292323003164315945381734567
-100233422360292323003164315945381734567
-100233422360292323003164315945381734567
115710133967357289505160160937439690295
115710133967357289505160160937439690295
...
```

And therefore the test throws:
```
java.lang.AssertionError:
Expected :2
Actual :1
```

Commencez par reproduire le test fourni autour de KllFloatsSketch.newHeapInstance(), heapify(), merge() et toByteArray(). Comparez les résultats sérialisés répétés lors de la fusion des sketches contenant 1 et 200 éléments, puis retracez le comportement de la fusion et de la sérialisation. Le travail est terminé lorsque le test répété produit un seul digest déterministe et réussit systématiquement.

Rédigé par le modèle d'indexation à partir du texte de l'issue.