Don't sort opcodes; move all pseudo-ops to the beginning

Don't sort opcodes; move all pseudo-ops to the beginning

We don't need to sort opcodes anymore, since we are using an O(1) hash
and not binary search.  Instead, sort them in the order they first
appear in insns.dat; this lets us move all the pseudo-ops to a
contiguous range at the start of the file, for more efficient
handling.

Change the functions that process pseudo-ops accordingly.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>