Fix bug and unit tests in LBD

[gustavo-marques]

Unit tests in the LBD were broken because 1) the syntax was incorrect (as pointed by @adcroft ), and 2) there was a bug in the bulk layer method. Both are fixed now and all unit tests are passing.

I've also fixed a string continuation syntax in MOM_tracer_registry.F90, caught by gcc 4.9.2.

[codecov-io]

Codecov Report

Merging #1092 into dev/gfdl will decrease coverage by 0.00%.
The diff coverage is 89.83%.

@@             Coverage Diff              @@
##           dev/gfdl    #1092      +/-   ##
============================================
- Coverage     45.80%   45.79%   -0.01%     
============================================
  Files           215      215              
  Lines         69480    69484       +4     
============================================
- Hits          31822    31819       -3     
- Misses        37658    37665       +7     

Impacted Files	Coverage Δ
src/tracer/MOM_tracer_registry.F90	89.65% <ø> (ø)
src/tracer/MOM_lateral_boundary_diffusion.F90	69.41% <88.00%> (-1.07%)	⬇️
src/framework/MOM_diag_mediator.F90	63.71% <100.00%> (ø)
src/framework/MOM_diag_remap.F90	92.79% <100.00%> (ø)

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[Hallberg-NOAA]

This PR is being tested with https://gitlab.gfdl.noaa.gov/ogrp/MOM6/pipelines/10245.

[Hallberg-NOAA]

Based on my visual inspection, this PR seems to be correct and reasonable. As this is a newer capability that is not being directly exercised by the MOM6-examples test suite, I will have to go on the assumption that this was properly tested by its trustworthy developer. Although this appears to add new run-time parameters, this change is conditional, and the MOM6-examples tests are not exhibiting changes to their MOM_parameter_doc files. However, the available_diags file does change, so this PR will have to be done by hand.