Add debug switch to capgen (perform variable allocation checks etc) + fix spelling: var_compatability --> var_compatibility

[climbfuji]

Update 2024/01/18: when pulling in feature/capgen, I noticed a spelling mistake that I corrected in commit 70ae2b0: var_compatability --> var_compatibility. I reran all the tests after pulling in feature/capgen and correcting the spelling, and they all passed.

This PR adds a --debug switch to capgen which enables checking of variables.

This feature is necessary for the transition from ccpp_prebuild.py to capgen.py. The following checks are performed:

1. If if the variable is not active (based on its active attribute), skip it
2. Variables that are allocatable or are pointers (scalars, arrays) and that have intent out for a scheme are skipped
3. For scalars that have intent in or inout, assign the current value to a dummy variable
4. For arrays, first check the size of the array against what's expected from the metadata, then assign the lower and upper bounds to a dummy (scalar) variable

User interface changes?: Yes
capgen now accepts an additional (but optional) argument --debug

This PR resolves #325. After adding the unit tests (see above), also #433

Testing:
test removed: none
unit tests: ran all unit tests in test/unit_tests
system tests:
- ran all Fortran tests in test/{advection_test,capgen_test,var_action_test}/ (note that the latter fail due to the missing unit conversions, but the new variable debug checks work as expected)
- ran doctests in scripts on all files modified
- ran hashtable tests in test/hashtable
manual testing: n/a

[climbfuji]

Self-review

[climbfuji]

@dustinswales @peverwhee @gold2718 I cleaned this up as discussed, it's now ready for review. I merged feature/capgen in cleanly after the constituents PR was merged and reran all the tests.

[dustinswales]

@climbfuji Looks good. Great job!

[peverwhee]

couple small comments, but nothing worthy of holding up the PR

[climbfuji]

@dustinswales @peverwhee @gold2718 After much debugging (or rather staring at the code and weeding through layers and layers of find_variable, I finally understand what was wrong with my code. I just pushed 7367f98 which makes two important updates:

• Fix the logic for finding variables that are local to the group in write_var_debug_checks. This allows us to enable allocation checks for locally-defined variables, part of this commit.
• Fix the logic to determine the horizontal dimensions. As it turns out, variables that are defined as module variables (i.e. managed by the suite) or that are defined locally (managed by the group) in the run phase always run from horizontal_loop_begin to horizontal_loop_end (and in all other phases from 1 to horizontal_dimension).

I added inline comments that explain the above in commit 7367f98. All doctstring tests and all capgen tests pass.

[climbfuji]

Pinging all remaining reviewers. This PR has sufficient approvals and we are planning to merge this PR on Wednesday, January 17 2024.

[climbfuji]

I am going to pull in feature/capgen today, resolve the conflicts, rerun all the tests and then merge unless someone requests changes today.

[climbfuji]

@dustinswales Can you please re-review the changes that I made to fix the spelling compatability --> compatibility after I pulled in feature/capgen? Commit 70ae2b0. If you could let me know then I will do a squashed merge with a proper commit message. Thanks!