Add more tests for C++ + OpenMP kernel

[mcbarton]

This PR exands upon the simple OpenMP kernel test xeus-cpp had, to several tests covering multiple openmp features.

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 73.51%. Comparing base (3c2b9d0) to head (36967f4).

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #477   +/-   ##
=======================================
  Coverage   73.51%   73.51%           
=======================================
  Files          23       23           
  Lines        1193     1193           
  Branches      111      111           
=======================================
  Hits          877      877           
  Misses        316      316           

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[mcbarton]

2 of the newly added tests fail on Ubuntu arm due to the lack of the __aarch64_ldadd4_relax symbol as far as I can tell. @vgvassilev any ideas what might be causing that symbol to be missing, or who to ask if you don't?

 FAILED test_xcpp_kernel.py::XCppOpenMPTests_xcpp23-omp::test_atomic - AssertionError: 'JIT session error: Symbols not found: [ _[176 chars] }\n' != '4'
+ 4
- JIT session error: Symbols not found: [ __aarch64_ldadd4_relax ]
- Failed to execute via ::process:Failed to materialize symbols: { (main, { $.incr_module_3.__inits.0, __orc_init_func.incr_module_3, _Z11main_atomicv }) }
-
FAILED test_xcpp_kernel.py::XCppOpenMPTests_xcpp23-omp::test_parallel_for_reduction - AssertionError: 'JIT session error: Symbols not found: [ _[230 chars] }\n' != '10'
+ 10
- JIT session error: Symbols not found: [ __aarch64_ldadd4_relax ]
- Failed to execute via ::process:Failed to materialize symbols: { (main, { .gomp_critical_user_.reduction.var, _Z27main_parallel_for_reductionv, $.incr_module_13.__inits.0, __orc_init_func.incr_module_13 }) }
-