Support C++20 iterators in raw_hash_map's random-access iterator detection

Missed in 9e764b4. Allows random-access iterators with a value-type `reference` (e.g. zip iterators) to hit this fast path, because of ae4b0c5.

PiperOrigin-RevId: 727356112
Change-Id: I4a2499cc1d0403b51a802297c84449531cfb9d5e

Author: Quincunx271

absl/container/BUILD.bazel

@@ -697,6 +697,7 @@ cc_library(
         "//absl/base:core_headers",
         "//absl/base:dynamic_annotations",
         "//absl/base:endian",
+        "//absl/base:iterator_traits_internal",
         "//absl/base:prefetch",
         "//absl/base:raw_logging_internal",
         "//absl/functional:function_ref",

absl/container/CMakeLists.txt

@@ -765,6 +765,7 @@ absl_cc_library(
     absl::hash_policy_traits
     absl::hashtable_debug_hooks
     absl::hashtablez_sampler
+    absl::iterator_traits_internal
     absl::memory
     absl::meta
     absl::optional

absl/container/internal/raw_hash_set.h

@@ -196,6 +196,7 @@
 #include "absl/base/attributes.h"
 #include "absl/base/config.h"
 #include "absl/base/internal/endian.h"
+#include "absl/base/internal/iterator_traits.h"
 #include "absl/base/internal/raw_logging.h"
 #include "absl/base/macros.h"
 #include "absl/base/optimization.h"
@@ -1601,10 +1602,8 @@ size_t SelectBucketCountForIterRange(InputIter first, InputIter last,
   if (bucket_count != 0) {
     return bucket_count;
   }
-  using InputIterCategory =
-      typename std::iterator_traits<InputIter>::iterator_category;
-  if (std::is_base_of<std::random_access_iterator_tag,
-                      InputIterCategory>::value) {
+  if (base_internal::IsAtLeastIterator<std::random_access_iterator_tag,
+                                       InputIter>()) {
     return GrowthToLowerboundCapacity(
         static_cast<size_t>(std::distance(first, last)));
   }