Update fates history tests to use double precision

[glemieux]

Description of changes

The current fates regression tests default to single precision. This PR updates to double precision

The PR resolves #1986

Specific notes

Contributors other than yourself, if any:
@ekluzek

CTSM Issues Fixed (include github issue #):

Are answers expected to change (and if so in what way)?
Yes

Any User Interface Changes (namelist or namelist defaults changes)?

Testing performed, if any:
(List what testing you did to show your changes worked as expected)
(This can be manual testing or running of the different test suites)
(Documentation on system testing is here: https://github.com/ESCOMP/ctsm/wiki/System-Testing-Guide)
(aux_clm on cheyenne for intel/gnu and izumi for intel/gnu/nag/pgi is the standard for tags on master)

NOTE: Be sure to check your coding style against the standard
(https://github.com/ESCOMP/ctsm/wiki/CTSM-coding-guidelines) and review
the list of common problems to watch out for
(https://github.com/ESCOMP/CTSM/wiki/List-of-common-problems).

[glemieux]

Regression testing the fates suite against baseline fates-sci.1.65.6_api.25.4.0-ctsm5.1.dev127 is showing diffs for all fates test modules as expected. Simple history outputs, like FATES_NCOHORTS and FATES_TVEG24, are showing round off errors of 10E-16.

I'll run this through the aux_clm tests shortly.

[glemieux]

Regression testing the aux_clm test suite on cheyenne and izumi are b4b with the exception of the expected DIFFs in all fates test mods.