When 2DMS or 2DMSArray is used, IMAGE_PARAMS will take an additional
paramter to represent sample number. The semantics check should get the
correct semantics values, taking this case into account.
Last year we changed 'volatile' to also act as 'coherent', but when I
resolved the memory model changes against that change I missed handling
volatile in a couple places that we check for coherent. There was also
a place in post-processing that acted as if the volatile memory access
flag has a literal number associated with it, when it doesn't.
