Fix the two sided test on IBMA Fishers and Stouffers estimators #1186

Job	Run time
Determine if CI should be skipped	3s
Unit tests with minimum dependency versions (ubuntu-latest, 3.8)	43m 8s
CBMR ImportError tests (ubuntu-latest, 3.8)	1m 1s
Unit tests (ubuntu-latest, 3.8)	42m 9s
Corrector performance tests (ubuntu-latest, 3.8)	30m 21s
Unit tests (ubuntu-latest, 3.9)	41m 12s
Unit tests (ubuntu-latest, 3.10)	44m 17s
Estimator performance tests (ubuntu-latest, 3.8)	6m 53s
Unit tests (ubuntu-latest, 3.11)	45m 46s
Smoke performance tests (ubuntu-latest, 3.8)	20m 38s
Unit tests (ubuntu-latest, 3.12)	41m 45s
Unit tests (macos-latest, 3.8)	44m 43s
Unit tests (macos-latest, 3.9)	25m 57s
Unit tests (macos-latest, 3.10)	22m 46s
Unit tests (macos-latest, 3.11)	23m 26s
Unit tests (macos-latest, 3.12)	23m 22s
Upload coverage	12s
	7h 37m 39s

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