The ARIA spec requires that, for certain landmark roles with no author-specified
names, user agents must treat such elements as if no role had been provided.
This revision accomplishes that task by carving out an exception in
ARIATransformRole and ComputeARIARole for roles::FORM, similar to the existing
carveout for roles::REGION. This revision also implements a NameIsEmpty function
which is helpful for checking name emptiness (since we do this in a few places)
without leaving a "name" variable on the stack. Finally, this revision updates a
expected WPT failure (by removing it).
Differential Revision: https://phabricator.services.mozilla.com/D202778
dbe5ffd60b