suzerain: #3089 Srho and friends in take_samples

Required:
# Moving Srho and friends to be non-implicit samples
# Removing gathering during nonlinear RHS
# Gathering statistics within take_samples
# Causing gold solutions to ignore the changed results
## HBL should of course ignore the results
## Prior results for channel.*, bl.explicit were NaNs and now zeros
   hence ignoring the new results

git-svn-id: https://svn.ices.utexas.edu/repos/pecos/suzerain/trunk@45117 0bd85f0b-c151-43b9-a1e9-27231104551f