[Issue 20548] Use bit vector instead of bool[] in RandomCover when choices cannot be packed in a single word

[d-bugmail at puremagic.com]

https://issues.dlang.org/show_bug.cgi?id=20548

--- Comment #3 from Dlang Bot <dlang-bot at dlang.rocks> ---
dlang/phobos pull request #7390 "Issue 20548 followup: in 32-bit builds
RandomCoverChoices allocates more memory than needed for the bit vector" was
merged into master:

- 67e4a0868472945818e9a417ea3c0ca4645b5fab by Nathan Sashihara:
  Issue 20548 followup: in 32-bit builds RandomCoverChoices allocates more
memory than needed for the bit vector

https://github.com/dlang/phobos/pull/7390

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