AD fix for CorrBijector #493

Job	Run time
test (1.6, ubuntu-latest, x64, ForwardDiff)	5m 27s
test (1.6, ubuntu-latest, x64, Tracker)	6m 50s
test (1.6, ubuntu-latest, x64, ReverseDiff)	6m 41s
test (1.6, ubuntu-latest, x64, Zygote)	8m 1s
test (1.6, macOS-latest, x64, ForwardDiff)	6m 38s
test (1.6, macOS-latest, x64, Tracker)	6m 55s
test (1.6, macOS-latest, x64, ReverseDiff)	6m 31s
test (1.6, macOS-latest, x64, Zygote)	8m 12s
test (1, ubuntu-latest, x64, ForwardDiff)	5m 46s
test (1, ubuntu-latest, x64, Tracker)	5m 57s
test (1, ubuntu-latest, x64, ReverseDiff)	7m 19s
test (1, ubuntu-latest, x64, Zygote)	7m 7s
test (1, macOS-latest, x64, ForwardDiff)	7m 23s
test (1, macOS-latest, x64, Tracker)	7m 32s
test (1, macOS-latest, x64, ReverseDiff)	8m 27s
test (1, macOS-latest, x64, Zygote)	8m 20s
	1h 53m 6s

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