[Tests] Relax assertion in SuggestStatsIT (#28544)

The test expects suggest times in milliseconds that are strictly
positive. Internally they are measured in nanos, it is possible that on
really fast execution this is rounded to 0L, so this should also be an
accepted value.

Closes #28543

server/src/test/java/org/elasticsearch/index/suggest/stats/SuggestStatsIT.java

@@ -112,7 +112,7 @@ public void testSimpleStats() throws Exception {
 
         logger.info("iter {}, iter1 {}, iter2 {}, {}", suggestAllIdx, suggestIdx1, suggestIdx2, endTime - startTime);
         // check suggest time
-        assertThat(suggest.getSuggestTimeInMillis(), greaterThan(0L));
+        assertThat(suggest.getSuggestTimeInMillis(), greaterThanOrEqualTo(0L));
         // the upperbound is num shards * total time since we do searches in parallel
         assertThat(suggest.getSuggestTimeInMillis(), lessThanOrEqualTo(totalShards * (endTime - startTime)));
 
@@ -124,7 +124,7 @@ public void testSimpleStats() throws Exception {
             logger.info("evaluating {}", stat.getNode());
             if (nodeIdsWithIndex.contains(stat.getNode().getId())) {
                 assertThat(suggestStats.getSuggestCount(), greaterThan(0L));
-                assertThat(suggestStats.getSuggestTimeInMillis(), greaterThan(0L));
+                assertThat(suggestStats.getSuggestTimeInMillis(), greaterThanOrEqualTo(0L));
                 num++;
             } else {
                 assertThat(suggestStats.getSuggestCount(), equalTo(0L));