Merge bitcoin#30281: Update leveldb subtree to latest upstream

a37778d Squashed 'src/leveldb/' changes from e2f10b4e47..688561cba8 (fanquake)

Pull request description:

  Includes bitcoin-core/leveldb-subtree#41 which is used in bitcoin#30234.

ACKs for top commit:
  theuni:
    utACK 95812d9

Tree-SHA512: 3d943695a3d33816cf5558b183f5629aa92a500a1544eecedf84952e93c8592a8cf0d554b88281fc0bad3c9e920ebcff1ed8edc12f8e73f36ed5335482beb829

src/leveldb/include/leveldb/status.h

@@ -103,6 +103,8 @@ class LEVELDB_EXPORT Status {
 inline Status::Status(const Status& rhs) {
   state_ = (rhs.state_ == nullptr) ? nullptr : CopyState(rhs.state_);
 }
+
+// NOLINTBEGIN(bugprone-unhandled-self-assignment)
 inline Status& Status::operator=(const Status& rhs) {
   // The following condition catches both aliasing (when this == &rhs),
   // and the common case where both rhs and *this are ok.
@@ -112,6 +114,8 @@ inline Status& Status::operator=(const Status& rhs) {
   }
   return *this;
 }
+// NOLINTEND(bugprone-unhandled-self-assignment)
+
 inline Status& Status::operator=(Status&& rhs) noexcept {
   std::swap(state_, rhs.state_);
   return *this;