Add option to use a more efficient tridiagonal solver for T & S in diabatic_ALE

[gustavo-marques]

Subroutine diabatic_ALE, which is what CESM/MOM6 uses, does not have the option to change T and S using the more efficient tridiagonal solver (triDiagTS_Eulerian). The current approach is to have two calls to tracer_vertdiff_Eulerian, one for T and one for S. Adding the option to use the more efficient solver triDiagTS_Eulerian might improve the throughput.