Merge #18664: fuzz: fix unused variable compiler warning

eab7367 fuzz: fix unused variable compiler warning (Jon Atack)

Pull request description:

  Fixes the compiler warning while hopefully not invalidating the existing seeds. Added an explanatory comment.
  ```
  test/fuzz/locale.cpp:59:19: warning: unused variable 'random_int32' [-Wunused-variable]
      const int32_t random_int32 = fuzzed_data_provider.ConsumeIntegral<int32_t>();
  ```

ACKs for top commit:
  practicalswift:
    ACK eab7367

Tree-SHA512: 4c90784518027cd3f85acd18030201efe4018f9da46365fef934e9a53a0b923031fec4c884a2da2f14232b6060aeb9016ac09950a18e31395de048548ecbc836

Author: MarcoFalke