Mapping of AccessibleStateType to AtkStateType

Hi

When trying to get the grips on "*Bug 86674* 
<https://bugs.freedesktop.org/show_bug.cgi?id=86674> - Previously-viewed 
paragraphs have ATK_STATE_INVALID after navigation by page" I realized 
that the issue was due to a few added AccessibleStateType's. The mapping 
into AtkStateType however was not updated. Problem is the current 
implementation expects all states to have an equivalent but I can only 
find an equivalent for DEFAULT. Not the other three added states. The 
added states are:
MOVEABLE
DEFAULT
OFFSCREEN
COLLAPSE

I did a small patch to fix DEFAULT and ignore MOVABLE. MOVABLE is 
causing the issue reported in the bug.
https://gerrit.libreoffice.org/#/c/13727

However the ignoring part is ugly. But I'm unsure of how to do it 
cleanly. At least ATK_STATE_INVALID does not get set if the state type 
is unmapped.

As a side note the added state COLLAPSE should probably be COLLAPSED. 
Could this be changed or is the name set in stone? If it is possible to 
change I need to verify that it really should be COLLAPSED and not COLLAPSE.

--
Regards,
Niklas