Small operands gcd improvements

[Torbjörn Granlund]

"Marco Bodrato" <bodrato at mail.dm.unipi.it> writes:

  > What's the purpose of this change?

  Failing tests :-)

Darn, my scripts must be buggy.

Let's leave the loop(s) alone, fix things outside.  The bd4 and zen2
code is also broken, I think.

This bug might have made my timing tests run faster than they should.
:o(

-- 
Torbjörn
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