[HOT FIX] Stabilize macOS CI tests: OpenMP linking, MPI env, per-test isolation #4243

Job	Run time
pre-commit / pre-commit	1m 19s
ubuntu / gcc-build (ubuntu-24.04-arm, Release)	2m 3s
ubuntu / gcc-build (ubuntu-24.04, Release)	2m 20s
ubuntu / gcc-build (ubuntu-24.04-arm, Debug)	1m 43s
ubuntu / gcc-build (ubuntu-24.04, Debug)	2m 34s
ubuntu / clang-build (ubuntu-24.04-arm)	2m 19s
mac / clang-build (Debug)	2m 28s
ubuntu / clang-build (ubuntu-24.04)	2m 39s
windows / clang-build	4m 13s
mac / clang-build (Release)	1m 59s
windows / msvc-build (Debug)	3m 56s
windows / msvc-build (Release)	4m 56s
mac / clang-test	5m 27s
ubuntu / gcc-test (ubuntu-24.04-arm)	8m 21s
ubuntu / gcc-test (ubuntu-24.04)	8m 35s
ubuntu / clang-sanitizer-build (ubuntu-24.04)	3m 19s
ubuntu / clang-test (ubuntu-24.04)	8m 22s
ubuntu / clang-test (ubuntu-24.04-arm)	8m 31s
windows / clang-test	3m 38s
windows / msvc-test	4m 38s
ubuntu / clang-sanitizer-test (ubuntu-24.04)	2m 51s
mac / clang-test-extended	3m 26s
windows / clang-test-extended	3m 15s
ubuntu / clang-sanitizer-test-extended (ubuntu-24.04)	2m 35s
windows / msvc-test-extended	3m 56s
ubuntu / gcc-test-extended (ubuntu-24.04-arm)	4m 41s
ubuntu / gcc-test-extended (ubuntu-24.04)	4m 35s
ubuntu / clang-test-extended (ubuntu-24.04)	4m 33s
ubuntu / clang-test-extended (ubuntu-24.04-arm)	4m 37s
ubuntu / gcc-build-codecov	7m 33s
perf / macos-clang-build-perf-stats	1m 59s
perf / ubuntu-gcc-build-perf-stats	1m 16s
pages / build-scoreboard	17s
pages / build-doxygen-xml	2m 50s
pages / build-sphinx	46s
pages / deploy-pages	0s
	2h 12m 30s

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