Eliminate use of internal interfaces

PiperOrigin-RevId: 479325483
Change-Id: I9c4384173ce996818e0cf749c0fc465d6e9aaf8c

absl/container/BUILD.bazel

@@ -1011,8 +1011,8 @@ cc_binary(
         ":flat_hash_set",
         ":hashtable_debug",
         "//absl/base:raw_logging_internal",
-        "//absl/flags:flag",
         "//absl/hash",
+        "//absl/log",
         "//absl/memory",
         "//absl/strings:cord",
         "//absl/strings:str_format",

absl/container/btree_benchmark.cc

@@ -34,8 +34,8 @@
 #include "absl/container/flat_hash_map.h"
 #include "absl/container/flat_hash_set.h"
 #include "absl/container/internal/hashtable_debug.h"
-#include "absl/flags/flag.h"
 #include "absl/hash/hash.h"
+#include "absl/log/log.h"
 #include "absl/memory/memory.h"
 #include "absl/strings/cord.h"
 #include "absl/strings/str_format.h"