tst_QLocalSocket::threadedConnection(): Add failure message.

Introduce QVERIFY2() to get some information when exactly it fails.

Change-Id: Icaddf2ecae434d0bafc90c18458c5ee067dfd506
Reviewed-by: Edward Welbourne <edward.welbourne@theqtcompany.com>
Reviewed-by: Jędrzej Nowacki <jedrzej.nowacki@theqtcompany.com>

tests/auto/network/socket/qlocalsocket/tst_qlocalsocket.cpp

@@ -732,7 +732,10 @@ public:
         int done = clients;
         while (done > 0) {
             bool timedOut = true;
-            QVERIFY(server.waitForNewConnection(7000, &timedOut));
+            QVERIFY2(server.waitForNewConnection(7000, &timedOut),
+                     (QByteArrayLiteral("done=") + QByteArray::number(done)
+                      + QByteArrayLiteral(", timedOut=")
+                      + (timedOut ? "true" : "false")).constData());
             QVERIFY(!timedOut);
             QLocalSocket *serverSocket = server.nextPendingConnection();
             QVERIFY(serverSocket);