LOW_VAL_CONTEXT_NODE
TWO_CONTEXT_NODE
THREE_CONTEXT_NODE
HIGH_LOW_CONTEXT_NODE
CAT_ONE_CONTEXT_NODE
CAT_THREEFOUR_CONTEXT_NODE
CAT_THREE_CONTEXT_NODE
CAT_FIVE_CONTEXT_NODE

unused since:
adaec4d0 Speeding up decode_coeffs().

Change-Id: Id07d2b0b76ff0ee6ef40d1b7a8e085e5e9e4aa8d