Change the default corpus weight method to "uniform".

Previous benchmarking showed that "uniform" performed the best.

PiperOrigin-RevId: 869236599

centipede/centipede_flags.inc

diff --git a/centipede/centipede_flags.inc b/centipede/centipede_flags.inc
index 1ab484b..650bd7c 100644
--- a/centipede/centipede_flags.inc
+++ b/centipede/centipede_flags.inc
@@ -192,9 +192,9 @@
     bool, use_corpus_weights, true,
     "If true, use weighted distribution when choosing the corpus element "
     "to mutate. This flag is mostly for Centipede developers.")
-CENTIPEDE_FLAG(std::string, corpus_weight_method, "feature_rarity",
+CENTIPEDE_FLAG(std::string, corpus_weight_method, "uniform",
                "The weight method to use on corpus. Available options are "
-               "`uniform`, `recency`, and `feature_rarity` (default).")
+               "`uniform` (default), `recency`, and `feature_rarity`.")
 CENTIPEDE_FLAG(
     bool, exec_time_weight_scaling, true,
     "If true, scale the corpus weight by the execution time of each input.")