Refactoring operation should wait for the Solr index to be empty before proceeding

Reproduction steps:

1. Log in as user "Admin" (when using a different user, adapt the title below).
2. Create a page named "Source".
3. Create a page with title

   #if($context.user != 'XWiki.Admin')#set($c = $datetool.getCalendar()) $c.add(13, 40) #foreach ($ci in [1..100000000000])#if ($datetool.getCalendar().after($c))#break#end#end#end Slow Title

   and a link to "Source" as content.

4. As fast as possible (within 20 seconds), rename "Source" to "Target".

Expected result:

The link is adapted.

Actual result:

The link isn't adapted.

With the fix, it is expected that a question if waiting shall continue appears after 10 seconds. If waiting is skipped, the link won't be updated. If waiting is continued, the rename operation waits until 40 seconds passed after the page has been created. If the question isn't answered, the question simply disappears after that time and the rename operation continues. The question shouldn't appear when updating incoming links is disabled for the rename operation.