Avoid I/O if not testing with fcompare #5320

Job	Run time
Save-PR-Number	3s
Formatting	15s
GPU-SYCL	31m 43s
CPU (ubuntu-24.04, Release, NoOpenMP)	15m 41s
Docker	13m 26s
GPU-HIP	22m 17s
CPU (ubuntu-24.04, Debug, OpenMP)	10m 32s
GPU-CUDA	27m 34s
CPU (ubuntu-24.04, Debug, NoOpenMP)	11m 32s
Lint-clang-tidy	32m 22s
Lint-codeql	16m 28s
CPU (macos-latest, Release, NoOpenMP)	2m 8s
Lint-codespell	7s
	3h 4m 8s

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