In fuzzing mode, `isc_random` uses a fixed seed for reproducibility.
The particular seed chosen happened to produce zero as its first
number, however commit bd251de0 introduced an initialization check in
`random_test` that required it to be non-zero. This change adjusts the
seed to avoid spurious test failures.
Also, remove the temporary variable that was used for initialization
because it did not match the type of the thread-local seed array.
Tony Finch
4b9af22830