Random: make statistical uniform tests fail less often (#52165)
We have a very basic test to check that a distribution might be uniform:
all the sampled elements should be unique, under certain conditions. But
these conditions allowed the tests to fail too often. So allow one
collision if the probability of such an event is too high.
Fix #52156.
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Co-authored-by: Kristoffer Carlsson <kcarlsson89@gmail.com>
