fs2000: remove asymptote in prior for rho, which caused corner solutions

tests/TeX/fs2000_corr_ME.mod

tests/conditional_forecasts/2/fs2000_est.mod

tests/dates/fs2000.mod

tests/estimation/MH_recover/fs2000.common.inc

tests/estimation/TaRB/fs2000_tarb.mod

...onditional-likelihood/1/fs2000_estimation_conditional.mod

...tion/conditional-likelihood/1/fs2000_estimation_exact.mod

tests/estimation/fs2000.mod

tests/estimation/fs2000_MCMC_jumping_covariance.mod

tests/estimation/fs2000_estimated_params_remove.mod

tests/estimation/fs2000_fast.mod

tests/estimation/fs2000_init_from_previous.mod

tests/estimation/fs2000_initialize_from_calib.mod

tests/estimation/fs2000_with_weibull_prior.mod

tests/estimation/independent_mh/fs2000_independent_mh.mod

.../no_init_estimation_check_first_obs/fs2000_init_check.mod

...it_estimation_check_first_obs/fs2000_init_check_XFAIL.mod

...t_estimation_check_first_obs/fs2000_init_check_XFAIL2.mod

tests/estimation/slice/fs2000_slice.mod

tests/estimation/t_proposal/fs2000_student.mod