Add digit separators to pre-evaluated results

Bug: 30362853

I missed this one additional case in which we need to add digit
separators.  This fix is relatively easy, since we ignore the
length added by digit separators when deciding how many digits to
display. SHORT_TARGET_LENGTH is only a heuristic anyway.

Change-Id: I5abed5d0d5c29a46089f619adcda3f1ecc7fe686