Support of withTip polyfill wrongly removed while considered as an API

We removed in XWIKI-23684 a polyfill supporting the behaviour of CSS classes "withTip" and "useTitleAsTip" because we considered it deprecated and using it in some part of XS was causing problems with our integration tests with Chrome. So back then, we haven't really checked more, considered it was buggy and removed it.

It appears that:
1. those classes were documented CSS classes of XWiki, so APIs
2. they are actually used in a lot of extensions
3. after checking again, we discovered that the Chrome bug appeared to be a regression in Chrome 4.38.0 as we apparently don't have problems anymore with our integration test using the behaviour with Chrome 4.39.0 and latest versions

On top of that we wrongly reacted very fast without making a formal proposal for removing it back then... For all those reasons we need to put back the polyfill allowing to have proper behaviour when using withTip and useTitleAsTip CSS classes.