reorder correlated error setup checks

[RussTreadon-NOAA]

Description
g-w issue #2507 flagged a gsi.x failure related to correlated error in a historical case. Rearranging the correlated error setup checks allows gsi.x to successfully run the historical case.

Fixes #735

Type of change

• Bug fix (non-breaking change which fixes an issue)

How Has This Been Tested?
Two tests have been conducted

1. Run failed 2021032418 case using updated gsi.x. GSI run to completion
2. Run ctests on Hera. All tests pass.

Test project /scratch1/NCEPDEV/da/Russ.Treadon/git/gsi/develop_test/build
    Start 1: global_4denvar
    Start 2: rtma
    Start 3: rrfs_3denvar_glbens
    Start 4: netcdf_fv3_regional
    Start 5: hafs_4denvar_glbens
    Start 6: hafs_3denvar_hybens
    Start 7: global_enkf
1/7 Test #4: netcdf_fv3_regional ..............   Passed  1209.16 sec
2/7 Test #3: rrfs_3denvar_glbens ..............Passed  1214.33 sec
3/7 Test #7: global_enkf ......................   Passed  1416.07 sec
4/7 Test #2: rtma .............................   Passed  1811.61 sec
5/7 Test #5: hafs_4denvar_glbens ..............   Passed  1887.12 sec
6/7 Test #6: hafs_3denvar_hybens ..............   Passed  1887.89 sec
7/7 Test #1: global_4denvar ...................   Passed  2468.95 sec

100% tests passed, 0 tests failed out of 7

Total Test time (real) = 2468.98 sec

Checklist

• My code follows the style guidelines of this project
• I have performed a self-review of my own code

[RussTreadon-NOAA]

@CatherineThomas-NOAA and @ADCollard - this PR contains the changes to src/gsi/correlated_obsmod.F90 described in g-w issue #2507.

I don't know the inner workings of correlated error. While the modified src/gsi/correlated_obsmod.F90 allows the failed case to pass, your review of the change would be greatly appreciated.

[ADCollard]

@RussTreadon-NOAA Thank you so much for fixing this. There is no reason for the code to exit in this case.

[CatherineThomas-NOAA]

Thanks for working out a fix to this, @RussTreadon-NOAA!

[RussTreadon-NOAA]

Orion ctests

Test project /work2/noaa/da/rtreadon/git/gsi/pr736/build
    Start 1: global_4denvar
    Start 2: rtma
    Start 3: rrfs_3denvar_glbens
    Start 4: netcdf_fv3_regional
    Start 5: hafs_4denvar_glbens
    Start 6: hafs_3denvar_hybens
    Start 7: global_enkf
1/7 Test #4: netcdf_fv3_regional ..............   Passed  544.36 sec
2/7 Test #3: rrfs_3denvar_glbens ..............   Passed  671.46 sec
3/7 Test #7: global_enkf ......................   Passed  798.60 sec
4/7 Test #2: rtma .............................   Passed  968.64 sec
5/7 Test #6: hafs_3denvar_hybens ..............   Passed  1167.65 sec
6/7 Test #5: hafs_4denvar_glbens ..............   Passed  1341.63 sec
7/7 Test #1: global_4denvar ...................   Passed  1745.74 sec

100% tests passed, 0 tests failed out of 7

Total Test time (real) = 1745.75 sec

Hercules ctests

Test project /work/noaa/da/rtreadon/git/gsi/pr736/build
    Start 1: global_4denvar
    Start 2: rtma
    Start 3: rrfs_3denvar_glbens
    Start 4: netcdf_fv3_regional
    Start 5: hafs_4denvar_glbens
    Start 6: hafs_3denvar_hybens
    Start 7: global_enkf
1/7 Test #4: netcdf_fv3_regional ..............   Passed  484.66 sec
2/7 Test #3: rrfs_3denvar_glbens ..............   Passed  551.02 sec
3/7 Test #7: global_enkf ......................   Passed  726.58 sec
4/7 Test #2: rtma .............................   Passed  965.16 sec
5/7 Test #6: hafs_3denvar_hybens ..............   Passed  1092.17 sec
6/7 Test #5: hafs_4denvar_glbens ..............   Passed  1226.01 sec
7/7 Test #1: global_4denvar ...................   Passed  1741.68 sec

100% tests passed, 0 tests failed out of 7

Total Test time (real) = 1741.89 sec

As expected, reordering the correlated error setup checks does not alter analysis results, wall time, or memory usage.

[RussTreadon-NOAA]

WCOSS2 (Dogwood) ctests

Test project /lfs/h2/emc/da/noscrub/russ.treadon/git/gsi/pr736/build
    Start 1: global_4denvar
    Start 2: rtma
    Start 3: rrfs_3denvar_glbens
    Start 4: netcdf_fv3_regional
    Start 5: hafs_4denvar_glbens
    Start 6: hafs_3denvar_hybens
    Start 7: global_enkf
1/7 Test #4: netcdf_fv3_regional ..............   Passed  483.67 sec
2/7 Test #3: rrfs_3denvar_glbens ..............   Passed  486.31 sec
3/7 Test #7: global_enkf ......................   Passed  851.93 sec
4/7 Test #2: rtma .............................   Passed  969.51 sec
5/7 Test #6: hafs_3denvar_hybens ..............   Passed  1153.08 sec
6/7 Test #5: hafs_4denvar_glbens ..............   Passed  1213.29 sec
7/7 Test #1: global_4denvar ...................   Passed  1682.47 sec

100% tests passed, 0 tests failed out of 7

Total Test time (real) = 1682.48 sec