Export of internal Abseil changes

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a9ea60e9c0ccd744b6f12fd021dbedfe826dfe84 by Matt Kulukundis <kfm@google.com>:

Add an internal hook to allow keeping flags in sync with global state.

Rollforward, except continue including hashtablez_flags.h in absl_flags.h so users don't break.

PiperOrigin-RevId: 412198044

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183e5c440b68c797ce4a82102f94f41c97a14674 by Martijn Vels <mvels@google.com>:

Internal cleanups and changes

PiperOrigin-RevId: 412083793

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3740faf7c5a2e1723e3c7e4d1b3f3db7cbec6e61 by Abseil Team <absl-team@google.com>:

Mark Cord::Clear() with the ABSL_ATTRIBUTE_REINITIALIZES attribute.

This prevents false positives in the clang-tidy check bugprone-use-after-move; it allows Clear() to be called on a moved-from Cord without any warnings, and the Cord will thereafter be regarded as initialized again.

PiperOrigin-RevId: 412082757

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a730d3f4ba06b55ae50386920a0544592069ac01 by Abseil Team <absl-team@google.com>:

StrJoin: Support iterators that do not have an `operator->`

Allows using `StrJoin` with iterators that do not have an `operator->`.
The `operator->` requirement for input iterators was dropped in C++20.

PiperOrigin-RevId: 412066130

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6773c0ced2caa6a7855898298faecc584f3997ec by Andy Soffer <asoffer@google.com>:

Rollback of internal hook for keeping flags in sync with global state.

PiperOrigin-RevId: 411895027

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4e7016a2fb88ce97853ef85ad5b4f76998eacca1 by Matt Kulukundis <kfm@google.com>:

Add an internal hook to allow keeping flags in sync with global state.

PiperOrigin-RevId: 411867376

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2a7d4056e467b6b5d8a7aa9398d6cb5454c10fc5 by Martijn Vels <mvels@google.com>:

Internal change

PiperOrigin-RevId: 411806932
GitOrigin-RevId: a9ea60e9c0ccd744b6f12fd021dbedfe826dfe84
Change-Id: Ib35bb7b40774979ed2ad205bbb1744b1085eae78

1 files changed, 16 insertions, 10 deletions

diff --git a/absl/strings/cord_test.cc b/absl/strings/cord_test.cc
index 8a311799..ea865cca 100644
--- a/absl/strings/cord_test.cc
+++ b/absl/strings/cord_test.cc
@@ -49,6 +49,11 @@ static constexpr auto MAX_FLAT_TAG = absl::cord_internal::MAX_FLAT_TAG;
 
 typedef std::mt19937_64 RandomEngine;
 
+using absl::cord_internal::CordRep;
+using absl::cord_internal::CordRepFlat;
+using absl::cord_internal::kFlatOverhead;
+using absl::cord_internal::kMaxFlatLength;
+
 static std::string RandomLowercaseString(RandomEngine* rng);
 static std::string RandomLowercaseString(RandomEngine* rng, size_t length);
 
@@ -266,10 +271,6 @@ INSTANTIATE_TEST_SUITE_P(WithParam, CordTest, testing::Values(0, 1, 2, 3),
 
 
 TEST(CordRepFlat, AllFlatCapacities) {
-  using absl::cord_internal::CordRep;
-  using absl::cord_internal::CordRepFlat;
-  using absl::cord_internal::kFlatOverhead;
-
   // Explicitly and redundantly assert built-in min/max limits
   static_assert(absl::cord_internal::kFlatOverhead < 32, "");
   static_assert(absl::cord_internal::kMinFlatSize == 32, "");
@@ -310,9 +311,6 @@ TEST(CordRepFlat, AllFlatCapacities) {
 }
 
 TEST(CordRepFlat, MaxFlatSize) {
-  using absl::cord_internal::CordRep;
-  using absl::cord_internal::CordRepFlat;
-  using absl::cord_internal::kMaxFlatLength;
   CordRepFlat* flat = CordRepFlat::New(kMaxFlatLength);
   EXPECT_EQ(flat->Capacity(), kMaxFlatLength);
   CordRep::Unref(flat);
@@ -323,15 +321,23 @@ TEST(CordRepFlat, MaxFlatSize) {
 }
 
 TEST(CordRepFlat, MaxLargeFlatSize) {
-  using absl::cord_internal::CordRep;
-  using absl::cord_internal::CordRepFlat;
-  using absl::cord_internal::kFlatOverhead;
   const size_t size = 256 * 1024 - kFlatOverhead;
   CordRepFlat* flat = CordRepFlat::New(CordRepFlat::Large(), size);
   EXPECT_GE(flat->Capacity(), size);
   CordRep::Unref(flat);
 }
 
+TEST(CordRepFlat, AllFlatSizes) {
+  const size_t kMaxSize = 256 * 1024;
+  for (size_t size = 32; size <= kMaxSize; size *=2) {
+    const size_t length = size - kFlatOverhead - 1;
+    CordRepFlat* flat = CordRepFlat::New(CordRepFlat::Large(), length);
+    EXPECT_GE(flat->Capacity(), length);
+    memset(flat->Data(), 0xCD, flat->Capacity());
+    CordRep::Unref(flat);
+  }
+}
+
 TEST_P(CordTest, AllFlatSizes) {
   using absl::strings_internal::CordTestAccess;