Have physics scheme tests check for compiler warnings

### What is the feature/what would you like to discuss?

It is oftentimes quite easy for compiler warnings to go unnoticed, even though they can reveal bugs that can cause real problems later.

To try and avoid that scenario, it would be great if all compiler warning messages were fixed for CAM-SIMA when using the `FPHYStest` compset and the relevant physics suites or schemes. Then when physics schemes are tested using the framework described in issue #230, a `-Werror` flag can be added to the GNU compiler calls that convert all compiler warnings to errors (which will result in a test failure if a warning appears). This way we can ensure that the CCPP-ized physics schemes generate no warnings, and have a mechanism that will quickly notify developers if new warnings show up in the future.

### Is there anyone in particular you want to be part of this conversation?

_No response_

### Will this change (regression test) answers?

I Don't Know

### Will you be implementing this enhancement yourself?

Any Software Engineer can do this

Start with the physics-testing framework described in issue #230 and the FPHYStest compset, then inspect how GNU compiler calls are configured for the relevant physics suites or schemes. Done means existing compiler warnings are fixed and the CCPP-ized physics scheme tests can use -Werror so future warnings fail the test.

Written by the indexing model from the issue text.