#1312 ScalarArray code generation

[mo-alistairp]

Adding code generation for ScalarArrays (towards #1312 ). The metadata support was added in #2173.

[arporter]

This isn't true I'm afraid - they will need to be added to a data region. However, you could leave this as a TODO as I'm not sure we're ever going to need data regions.

[mo-alistairp]

Thanks for that - it's currently a very rough draft so some of the comments are currently just borrowed from other functions. But, I will definitely note that down!

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 99.91%. Comparing base (97dd02d) to head (5d92498).

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #3101      +/-   ##
==========================================
- Coverage   99.91%   99.91%   -0.01%     
==========================================
  Files         376      377       +1     
  Lines       53529    53627      +98     
==========================================
+ Hits        53484    53581      +97     
- Misses         45       46       +1     

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[mo-alistairp]

This still isn't working as intended, but is getting closer to correct. As an example, the code gen is now adding the scalar arrays to the generated code, alongside the arrays containing their dimensions. However, it is not adding these dimensions to the generated code (e.g., no dimensions(...) mention). It is also assigning the field as intent(in) right now, which it shouldn't do either.

Furthermore, the stub_gen test is failing because we are currently adding the dimensions array to the psyir layer as an ArgumentInteraface which isn't there as an argument at the call. Need to find a way around this. I'm wondering if we need a dimensions array at all but I'll have to investigate that further.

[mo-alistairp]

I'm having a little trouble getting testkern_scalar_array_mod via lfric_scalar_codegen_test to compile. Currently, it's erroring with
Error: Symbol 'gh_scalar_array' at (1) has no IMPLICIT type; did you mean 'gh_scalar'?

Still trying to find what needs adding to fix this.