Allow for multiple instances of local_name in Cap.

[dustinswales]

Description

Allow for multiple instances of the same local_name being used in the Group cap:
a) with different standard_names
b) as part of different DDTs.

Steps to Reproduce

Using the var_compatability_test, add three new scalar variables (e.g. var_a, var_b, and var_c) that use the same local_name (scalar_var) within the Group. Then pass scalar_var_a into effrr_pre, scalar_var_b into effrr_post, and scalar_var_c into effrr_diag,
This will create a fortran runtime error due to the fact the same local_name is used three times within the Cap, scalar_var1.

@cacraigucar You mentioned an issue with reusing the same local_name, so it's possible this will address that.