legend text fieldset test

PASS if fieldset element maps to one of the following:

MSAA + UIA Express role

MSAA + IAccessible2 role and

other IAccessible2 features

ATK/AT-SPI role

Mac OS X

AXRole
AXSubrole
AXRoleDescription

ROLE_SYSTEM_GROUPING ROLE_SYSTEM_GROUPING ROLE_PANEL AXGroup
<nil>
'group'

FAIL otherwise.