[405b-SUT] Max number of output tokens

[attafosu]

For 405B the sampling parameter config sets the max output tokens to be 20k.
However, given the reference output distribution with max output length of 1.7k, I don't think we should set this parameter in the sampler that high.
@nvzhihanj @arjunsuresh @mrmhodak

[nvzhihanj]

max_new_tokens should be 2000 (max input length is 20000), this looks like a typo. Can you help submit a PR to patch it?