Merge bitcoin/bitcoin#24050: validation: Give m_block_index ownership of CBlockIndexs

6c23c41561 refactor: Rewrite AddToBlockIndex with try_emplace (Carl Dong)
c05cf7aa1e style: Modernize range-based loops over m_block_index (Carl Dong)
c2a1655799 style-only: Use using instead of typedef for BlockMap (Carl Dong)
dd79dad175 refactor: Rewrite InsertBlockIndex with try_emplace (Carl Dong)
531dce0347 tests: Remove now-unnecessary manual Unload's (Carl Dong)
bec86ae326 blockstorage: Make m_block_index own CBlockIndex's (Carl Dong)

Pull request description:

  Part of: #24303
  Split off from: #22564

  ```
  Instead of having CBlockIndex's live on the heap, which requires manual
  memory management, have them be owned by m_block_index. This means that
  they will live and die with BlockManager.
  ```

  The second commit demonstrates how this makes calls to `Unload()` to satisfy the address sanitizer unnecessary.

ACKs for top commit:
  ajtowns:
    ACK 6c23c41561
  MarcoFalke:
    re-ACK 6c23c41561 🎨

Tree-SHA512: 81b2b5119be27cc0f8a9457b11da60cc60930315d2a5be36be89fe253d32073ffe622348ff153114b9b3212197bddbc791810913a43811b33cc58e7162bd105b

src/wallet/test/wallet_tests.cpp

@@ -367,10 +367,10 @@ static int64_t AddTx(ChainstateManager& chainman, CWallet& wallet, uint32_t lock
     CBlockIndex* block = nullptr;
     if (blockTime > 0) {
         LOCK(cs_main);
-        auto inserted = chainman.BlockIndex().emplace(GetRandHash(), new CBlockIndex);
+        auto inserted = chainman.BlockIndex().emplace(std::piecewise_construct, std::make_tuple(GetRandHash()), std::make_tuple());
         assert(inserted.second);
         const uint256& hash = inserted.first->first;
-        block = inserted.first->second;
+        block = &inserted.first->second;
         block->nTime = blockTime;
         block->phashBlock = &hash;
         state = TxStateConfirmed{hash, block->nHeight, /*position_in_block=*/0};