Added additional test for regime of parameterized_truncated_normal sampler.

In the case where the stddev is small relative to the bounds, the sampler
is currently generating some outliers.

Added warning logging if the sampler terminates before sampling successfully.

Increased kMaxIterations from 100 to 1000 (this may not be a good long-term
solution but, in general, users probably prefer additional computation to
spurious outliers).

PiperOrigin-RevId: 209583394