clm5/cime_config/testdefs/testmods_dirs/clm/ciso_cwd_hr

This points to an alternate params file with
rf_cwdl2     = 0.5
rf_cwdl3_bgc = 0.5
while by default these parameters equal zero.

The test outputs inactive history fields that would contain zeros
when running with the default params file and should be greater than zero
when running with the alternate params file.