[Issue 18332] rt.util.random.Rand48 remove unnecessary assert

[d-bugmail at puremagic.com]

https://issues.dlang.org/show_bug.cgi?id=18332

--- Comment #2 from Nathan S. <n8sh.secondary at hotmail.com> ---
Fix in https://github.com/dlang/druntime/pull/2069

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