Use `safeAwait` in `indexRandom` (#124362)

No need to implement the safe wait on the latch by hand here, we can use
the other `safeAwait` variant that takes a timeout. Also adds a comment
discouraging its use elsewhere without good reason.

test/framework/src/main/java/org/elasticsearch/test/ESIntegTestCase.java

@@ -213,6 +213,7 @@ import static org.elasticsearch.cluster.metadata.IndexMetadata.SETTING_NUMBER_OF
 import static org.elasticsearch.cluster.metadata.IndexMetadata.SETTING_NUMBER_OF_SHARDS;
 import static org.elasticsearch.common.util.CollectionUtils.eagerPartition;
 import static org.elasticsearch.core.TimeValue.timeValueMillis;
+import static org.elasticsearch.core.TimeValue.timeValueSeconds;
 import static org.elasticsearch.discovery.DiscoveryModule.DISCOVERY_SEED_PROVIDERS_SETTING;
 import static org.elasticsearch.discovery.SettingsBasedSeedHostsProvider.DISCOVERY_SEED_HOSTS_SETTING;
 import static org.elasticsearch.index.IndexSettings.INDEX_SOFT_DELETES_RETENTION_LEASE_PERIOD_SETTING;
@@ -1887,16 +1888,8 @@ public abstract class ESIntegTestCase extends ESTestCase {
             }
         }
         while (inFlightAsyncOperations.size() > MAX_IN_FLIGHT_ASYNC_INDEXES) {
-            int waitFor = between(0, inFlightAsyncOperations.size() - 1);
-            try {
-                assertTrue(
-                    "operation did not complete within timeout",
-                    inFlightAsyncOperations.remove(waitFor).await(60, TimeUnit.SECONDS)
-                );
-            } catch (InterruptedException e) {
-                Thread.currentThread().interrupt();
-                fail(e, "interrupted while waiting for operation to complete");
-            }
+            // longer-than-usual timeout, see #112908
+            safeAwait(inFlightAsyncOperations.remove(between(0, inFlightAsyncOperations.size() - 1)), timeValueSeconds(60));
         }
     }
 

test/framework/src/main/java/org/elasticsearch/test/ESTestCase.java

@@ -2429,6 +2429,10 @@ public abstract class ESTestCase extends LuceneTestCase {
     /**
      * Await on the given {@link CountDownLatch} with a supplied timeout, preserving the thread's interrupt status
      * flag and asserting that the latch is indeed completed before the timeout.
+     * <p>
+     * Prefer {@link #safeAwait(CountDownLatch)} (with the default 10s timeout) wherever possible. It's very unusual to need to block a
+     * test for more than 10s, and such slow tests are a big problem for overall test suite performance. In almost all cases it's possible
+     * to find a different way to write the test which doesn't need such a long wait.
      */
     public static void safeAwait(CountDownLatch countDownLatch, TimeValue timeout) {
         try {