Fix call to tryCompare in tst_download.qml

tryCompare insists on getting the name of the property to be checked as
a string.

Change-Id: Ic879281305e3055eb8e0ff2092a74b6dba06f87a
Reviewed-by: Allan Sandfeld Jensen <allan.jensen@qt.io>

tests/auto/quick/qmltests/data/tst_download.qml

@@ -114,7 +114,7 @@ TestWebEngineView {
             compare(downloadState[1], WebEngineDownloadItem.DownloadInProgress)
             downloadFinishedSpy.wait()
             compare(totalBytes, receivedBytes)
-            tryCompare(downloadState, 2, WebEngineDownloadItem.DownloadCompleted)
+            tryCompare(downloadState, "2", WebEngineDownloadItem.DownloadCompleted)
         }
 
         function test_downloadCancelled() {