Use an even better random number generation scheme in the prune test

client/prune_crash_reports_test.cc

Index: client/prune_crash_reports_test.cc
diff --git a/client/prune_crash_reports_test.cc b/client/prune_crash_reports_test.cc
index 7ffe67bc09ece82623b0812fb695282fea8fc5df..bb9ea8e2b0b2e6296eb0b3c1bbd78beadd278041 100644
--- a/client/prune_crash_reports_test.cc
+++ b/client/prune_crash_reports_test.cc
@@ -208,7 +208,7 @@ TEST(PruneCrashReports, PruneOrder) {
   }
   // The randomness from std::rand() is not, so use a better rand() instead.
   const auto random_generator = [](int rand_max) {
-    return base::RandUint64() % rand_max;
+    return base::RandInt(0, rand_max - 1);
   };
   std::random_shuffle(reports.begin(), reports.end(), random_generator);
   std::vector<CrashReportDatabase::Report> pending_reports(