Truncate over-long strings of 9s.

We use long strings of 9s as bounding values for integers.  On 32-bit
values, if those long strings exceed 999999999 the resulting int wraps
and is smaller, so don't use more than nine 9s in a row.
Merge pull request #311 from ediosyncratic/too-many-nines-fixes

Truncate over-long strings of 9s.