Fix the two sided test on IBMA Fishers and Stouffers estimators #1188

Job	Run time
Determine if CI should be skipped	6s
Corrector performance tests (ubuntu-latest, 3.8)	31m 11s
Unit tests (ubuntu-latest, 3.8)	39m 27s
Unit tests with minimum dependency versions (ubuntu-latest, 3.8)	50m 2s
Unit tests (ubuntu-latest, 3.9)	56m 13s
CBMR ImportError tests (ubuntu-latest, 3.8)	1m 52s
Estimator performance tests (ubuntu-latest, 3.8)	20m 21s
Unit tests (ubuntu-latest, 3.10)	40m 47s
Unit tests (ubuntu-latest, 3.11)	40m 9s
Smoke performance tests (ubuntu-latest, 3.8)	21m 30s
Unit tests (ubuntu-latest, 3.12)	41m 29s
Unit tests (macos-latest, 3.8)	48m 1s
Unit tests (macos-latest, 3.9)	29m 23s
Unit tests (macos-latest, 3.10)	23m 52s
Unit tests (macos-latest, 3.11)	25m 28s
Unit tests (macos-latest, 3.12)	27m 38s
Upload coverage	12s
	8h 17m 41s

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