[TEST} unmutes SearchAsyncActionTests and adds debugging info

This unmutes the testFanOutAndCollect()` method and add a check to make
sure we aren't accidentally running something twice causing a search
phase to still be running after we have counted down the latch

Relates to #29242

Author: colings86

server/src/test/java/org/elasticsearch/action/search/SearchAsyncActionTests.java

@@ -256,7 +256,6 @@ public void run() {
         assertEquals(10, numRequests.get());
     }
 
-    @AwaitsFix(bugUrl = "https://github.com/elastic/elasticsearch/issues/29242")
     public void testFanOutAndCollect() throws InterruptedException {
         SearchRequest request = new SearchRequest();
         request.allowPartialSearchResults(true);
@@ -347,6 +346,9 @@ public void run() throws IOException {
                             sendReleaseSearchContext(result.getRequestId(), new MockConnection(result.node), OriginalIndices.NONE);
                         }
                         responseListener.onResponse(response);
+                        if (latch.getCount() == 0) {
+                            throw new AssertionError("Running a search phase after the latch has reached 0 !!!!");
+                        }
                         latch.countDown();
                     }
                 };