Revert "TableSorter: Avoid FOUC and preserve styling in VisualEditor"

That was, unfortunately, way too optimistic. The logic for
choosing header cells that are used for sorting is a lot more
complicated than current CSS selectors can express.

This reverts commit 9e363d0e8a12f4fc205de08958622d6e8e250c81.

Bug: T126007
Change-Id: I7c08e06a4f61d69b6858958218d9a6233aee18de