compiler: fix msd thickness lowering #375

Job	Run time
pytest-docker-py310-gcc-omp-arm64-base	32m 37s
pytest-docker-py310-gcc-omp-base	38m 40s
pytest-docker-py310-gcc-omp-adjoint	26m 48s
pytest-docker-py310-icx-omp-adjoint	29m 54s
pytest-docker-py310-gcc-omp-arm64-adjoint	25m 3s
pytest-docker-py310-icx-omp-base	33m 16s
pytest-ubuntu-py311-gcc11-cxxnoomp-adjoint	34m 44s
pytest-ubuntu-py312-gcc12-cxxomp-adjoint	42m 37s
pytest-ubuntu-py310-gcc14-omp-adjoint	26m 52s
pytest-ubuntu-py310-gcc14-omp-base	44m 48s
pytest-ubuntu-py312-gcc12-cxxomp-base	57m 58s
pytest-osx-py312-clang-omp-base	30m 53s
pytest-ubuntu-py312-gcc13-omp-adjoint	36m 24s
pytest-ubuntu-py310-gcc9-omp-adjoint	35m 21s
pytest-ubuntu-py312-gcc13-omp-base	53m 59s
pytest-ubuntu-py311-gcc10-noomp-adjoint	32m 21s
pytest-ubuntu-py313-gcc14-omp-adjoint	42m 2s
pytest-ubuntu-py313-gcc14-omp-base	46m 37s
pytest-ubuntu-py311-gcc11-cxxnoomp-base	44m 5s
pytest-ubuntu-py311-gcc10-noomp-base	40m 25s
pytest-ubuntu-py310-gcc9-omp-base	46m 54s
	13h 22m 18s

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