[Embedding] Add double check in find_wait_free of lockless dense hashmap.

Signed-off-by: lixy9474 <lxy268263@alibaba-inc.com>

Author: lixy9474

third_party/sparsehash_c11.patch

@@ -1,21 +1,21 @@
-From e40cddd160fbec51b3309bb56c72a3258bfe69b6 Mon Sep 17 00:00:00 2001
+From dcd5910ddff22b2896dc5221eab766a6c6d2307d Mon Sep 17 00:00:00 2001
 From: Tongxuan Liu <tongxuan.ltx@alibaba-inc.com>
 Date: Mon, 13 Mar 2023 08:58:56 +0800
-Subject: [PATCH] [PATCH] Avoid fetching nullptr when use feature filter.
+Subject: [PATCH] Avoid fetching nullptr when use feature filter.
 
 ---
  Makefile                                      |   13 +-
  sparsehash/dense_hash_map_lockless            |  447 ++++
- sparsehash/dense_hash_set_lockless            |  381 ++++
+ sparsehash/dense_hash_set_lockless            |  381 +++
  sparsehash/internal/densehashtable.h          |   16 +-
- sparsehash/internal/densehashtable_lockless.h | 2032 +++++++++++++++++
+ sparsehash/internal/densehashtable_lockless.h | 2033 +++++++++++++++++
  sparsehash/internal/hashtable-common.h        |    4 +
  sparsehash/internal/sparsehashtable.h         |   18 +-
  sparsehash/traits                             |   10 +-
  tests/bench_lockless.cc                       | 1466 ++++++++++++
  tests/dense_hash_map_unittests.cc             |  137 +-
  tests/rwlock.h                                |  224 ++
- 11 files changed, 4725 insertions(+), 23 deletions(-)
+ 11 files changed, 4726 insertions(+), 23 deletions(-)
  create mode 100644 sparsehash/dense_hash_map_lockless
  create mode 100644 sparsehash/dense_hash_set_lockless
  create mode 100644 sparsehash/internal/densehashtable_lockless.h
@@ -958,10 +958,10 @@ index e254126..3bc3c16 100644
      for (; dist > 0; --dist, ++f) {
 diff --git a/sparsehash/internal/densehashtable_lockless.h b/sparsehash/internal/densehashtable_lockless.h
 new file mode 100644
-index 0000000..c13c628
+index 0000000..64f677f
 --- /dev/null
 +++ b/sparsehash/internal/densehashtable_lockless.h
-@@ -0,0 +1,2032 @@
+@@ -0,0 +1,2033 @@
 +// Copyright (c) 2005, Google Inc.
 +// All rights reserved.
 +//
@@ -2204,7 +2204,8 @@ index 0000000..c13c628
 +      }else if(test_deleted(bucknum, tmp_pointer)) {
 +        if(insert_pos == ILLEGAL_BUCKET) insert_pos = bucknum;
 +      }else if (equals(key, get_key(tmp_pointer->table_[bucknum]))) {
-+        std::pair<K, T> tmp(key, tmp_pointer->table_[bucknum].second);
++        std::pair<K, T> tmp(tmp_pointer->table_[bucknum].first,
++                            tmp_pointer->table_[bucknum].second);
 +        if(tmp.first == key){
 +          return tmp;
 +        }else{
@@ -4949,5 +4950,5 @@ index 0000000..25e8e93
 +};
 \ No newline at end of file
 -- 
-2.37.1
+2.25.1