DBW: use touch-action instead of restricting movement in code

CSS `touch-action` is a more performant way to restrict touch movement of a region.

https://developer.mozilla.org/en-US/docs/Web/CSS/touch-action

We can probably use the [document level event listener gatherer](https://github.com/GoogleChrome/lighthouse/blob/master/lighthouse-core/gather/gatherers/dobetterweb/document-event-listeners.js) for this.

http://jsbin.com/qibakekiri/edit?html,output

Read the document-event-listeners.js gatherer referenced in the issue and review the linked MDN touch-action documentation and JSBin example. Trace how the DBW check currently identifies movement restrictions, then define the relevant test or audit expectation before making the change; done means the intended touch-action usage is correctly recognized without the existing code-based restriction.

Written by the indexing model from the issue text.