pr-preview hides mapping tables in CORE-AAM and HTML-AAM previews

[carmacleod]

pr-preview hides the mapping tables in all CORE-AAM and HTML-AAM PR previews (maybe also in other AAM specs - didn't check).
Since mapping tables are a key feature of AAM specs, this is an unfortunate omission.

I suspect that the problem is somewhere in aria-common/script/mapping-tables.js (presumably in one of the places where the .table-container is told to .hide(), for example, $(this).hide(); ), and I suspect that the issue may have something to do with deprecated ReSpec events. I don't know how to debug and test pr-preview without creating fake PR(s), which would send everyone a bunch of "debug code" notifications. 😄

Note that the tables are actually in the preview - they're just hidden. You can get them to show up by going into devtools and removing style="display: none;" from each element that has class="table-container", but this is not something that most people guess when they are simply reviewing a PR, so it is an unfortunate source of confusion and a potential time sink for reviewers.

Not sure if this issue is related to: #7