Change a reproducible sum algorithm in SI solver

[hyungyukang]

Change a reproducible sum algorithm in the ocean split-implicit barotropic mode solver. The changed algorithm uses a global reproducible summation module in components/mpas-framework/src/framework/mpas_global_sum_mod.F

This PR passed PEM_Ln9_D.T62_oQU240.GMPAS-IAF.cori-knl_gnu test with config_time_integrator = 'split_implicit' and config_btr_si_partition_match_mode = .true..

[BFB]

[philipwjones]

Approve based on code inspection and the previous successful PEM test that shows the sums themselves are reproducible across node configurations. Note that the branch naming convention uses hyphens and not underscores.

The new algorithm is not likely to give a bfb result compared to the old, so I'm guessing the bfb flag here is because this option is off by default?

[hyungyukang]

Approve based on code inspection and the previous successful PEM test that shows the sums themselves are reproducible across node configurations. Note that the branch naming convention uses hyphens and not underscores.

The new algorithm is not likely to give a bfb result compared to the old, so I'm guessing the bfb flag here is because this option is off by default?

@philipwjones , thanks for reviewing and approving this PR. Exactly. The config_btr_si_partition_match_mode is turned off by default, so the SI solver with default options is exactly the same with a previous version.

[jonbob]

Test merge passes:

• ERS.ne11_oQU240.WCYCL1850NS.chrysalis_intel
• SMS_P12x2.ne4_oQU240.WCYCL1850NS.chrysalis_intel.allactive-mach_mods
• SMS_D_Ld3.T62_oQU120.CMPASO-IAF.chrysalis_intel

merged to next

[jonbob]

merged to master