Port subset of em_real tests from regression tests

[islas]

TYPE: enhancement

KEYWORDS: testing, em_real

SOURCE: internal

DESCRIPTION OF CHANGES:
Problem:
In the continued effort to port the regression tests to a usable format outside a single container environment, a generalized testing framework is now in place. However, this currently lacks the full set of tests.

Solution:
This implements a subset of the em_real tests, notably the tests that are stable, bitwise reproducible, and do not rely on in situ modification of configuration.

TESTS CONDUCTED:

1. Testing was done on Derecho and local machine to recreate the running of the test namelists, gather the testing data, and coordinate the tests. Through process of elimination, tests were removed that did not provide consistent pass results. This is not ideal for robust testing, but demonstrates the fragility of the tests outside a pristine containerized environment.

[weiwangncar]

The regression test results:

Test Type              | Expected  | Received |  Failed
= = = = = = = = = = = = = = = = = = = = = = = =  = = = =
Number of Tests        : 23           24
Number of Builds       : 60           57
Number of Simulations  : 158           150        0
Number of Comparisons  : 95           86        0

Failed Simulations are: 
None
Which comparisons are not bit-for-bit: 
None

[islas]

@kkeene44 or @weiwangncar (who ever is more familiar with the Scala tests) I think it would be good for someone to spot-check this to make sure I have the equivalent logic being used in Scala tests to run the namelists.

The analogous info from large test matrix found in the Scala tests can be found in the .ci/wrf_em_real_tests.jsonc file.