Merge bitcoin/bitcoin#35808: fuzz: reset connman state in p2p targets

d29b22d078 fuzz: reset connman state in p2p targets (Hao Xu)

Pull request description:

  Resets `ConnmanTestMsg` at the start of each input in `cmpctblock` and `p2p_handshake`, matching the other reused-connman fuzz targets and preventing sticky `CConnman` state from leaking between corpus inputs.

  Before this, deterministic-fuzz-coverage showed single inputs were stable, but all-input directory runs were not:

  ```diff
  cmpctblock, src/net.cpp:4172
  - Branch (4172:9): [True: 1.21k, False: 33.0k]
  + Branch (4172:9): [True: 613, False: 33.6k]
  - Branch (4172:72): [True: 901, False: 311]
  + Branch (4172:72): [True: 497, False: 116]
  ```

  ```diff
  p2p_handshake, src/net.cpp:4172
  - Branch (4172:9): [True: 98, False: 1.67k]
  + Branch (4172:9): [True: 743, False: 1.03k]
  - Branch (4172:72): [True: 90, False: 8]
  + Branch (4172:72): [True: 612, False: 131]
  ```

  With the resets, `deterministic-fuzz-coverage` passed for both `cmpctblock` and `p2p_handshake`.

ACKs for top commit:
  nervana21:
    re-tACK d29b22d078
  maflcko:
    lgtm ACK d29b22d078

Tree-SHA512: bd445ae33ab7f9850046e3de4e318bee9ae7b38ee77ee282d0f5c3a88a4b67610dd00faef2af913a4d7d42bfc42b957855b2d85f1849f77823149baa089afce2

src/test/fuzz/cmpctblock.cpp

@@ -126,6 +126,8 @@ FUZZ_TARGET(cmpctblock, .init = initialize_cmpctblock)
     FakeSteadyClock steady_clock;
 
     auto setup = g_setup;
+    auto& connman = *static_cast<ConnmanTestMsg*>(setup->m_node.connman.get());
+    connman.Reset();
     auto& mempool = *setup->m_node.mempool;
     auto& chainman = static_cast<TestChainstateManager&>(*setup->m_node.chainman);
     chainman.ResetIbd();
@@ -133,7 +135,6 @@ FUZZ_TARGET(cmpctblock, .init = initialize_cmpctblock)
     const size_t initial_index_size{WITH_LOCK(chainman.GetMutex(), return chainman.BlockIndex().size())};
 
     AddrMan addrman{*setup->m_node.netgroupman, /*deterministic=*/true, /*consistency_check_ratio=*/0};
-    auto& connman = *static_cast<ConnmanTestMsg*>(setup->m_node.connman.get());
     auto peerman = PeerManager::make(connman, addrman,
                                      /*banman=*/nullptr, chainman,
                                      mempool, *setup->m_node.warnings,

src/test/fuzz/p2p_handshake.cpp

@@ -40,6 +40,7 @@ FUZZ_TARGET(p2p_handshake, .init = ::initialize)
 
     auto& node{g_setup->m_node};
     auto& connman{static_cast<ConnmanTestMsg&>(*node.connman)};
+    connman.Reset();
     auto& chainman{static_cast<TestChainstateManager&>(*node.chainman)};
     FakeNodeClock clock{1610000000s}; // 2021-01-07, arbitrary
     FakeSteadyClock steady_clock;