gas: drop tic6x scrubber special case

Two successive PUT() without a state change in between can't be right:
The first PUT() may take the "goto tofull" path, leading to the
subsequent character being processed later in the previously set state
(1 in this case), rather than the state we were in upon entry to the
switch() (13 in this case).

However, the original purpose of that logic appears to be to not mistake
"|| ^" for "||^". This effect, sadly, looks to not have been achieved.
Therefore drop the special case altogether; something that actually
achieves the (presumably) intended effect may then be introduced down
the road.