Merge bitcoin#23573: refactor: cast bool operands to int to silence compiler warning

ab22a71 refactor: cast bool to int to silence compiler warning (Jon Atack)

Pull request description:

  This fixes a compiler warning:
  ```
  node/interfaces.cpp:544:16: warning: use of bitwise '&' with boolean operands [-Wbitwise-instead-of-logical]
          return FillBlock(ancestor, ancestor_out, lock, active) & FillBlock(block1, block1_out, lock, active) & FillBlock(block2, block2_out, lock, active);
                 ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
                                                                                                               &&
  node/interfaces.cpp:544:16: note: cast one or both operands to int to silence this warning
  node/interfaces.cpp:544:16: warning: use of bitwise '&' with boolean operands [-Wbitwise-instead-of-logical]
          return FillBlock(ancestor, ancestor_out, lock, active) & FillBlock(block1, block1_out, lock, active) & FillBlock(block2, block2_out, lock, active);
                 ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
                                                                 &&
  node/interfaces.cpp:544:16: note: cast one or both operands to int to silence this warning
  2 warnings generated.
  ```

ACKs for top commit:
  sipa:
    utACK ab22a71
  theStack:
    Concept and code-review ACK ab22a71
  shaavan:
    ACK ab22a71

Tree-SHA512: 84e5aeabc1514a7586ac7c78a8eff1d15a5967dced7b2485b266b6fd79a530e1b22d99ded0a5df39f7806d3c5fd6d9752f08a722cc3be17850a6242c4022ab03

Author: fanquake

src/node/interfaces.cpp

@@ -540,8 +540,11 @@ class ChainImpl : public Chain
         const CBlockIndex* block2 = m_node.chainman->m_blockman.LookupBlockIndex(block_hash2);
         const CBlockIndex* ancestor = block1 && block2 ? LastCommonAncestor(block1, block2) : nullptr;
         // Using & instead of && below to avoid short circuiting and leaving
-        // output uninitialized.
-        return FillBlock(ancestor, ancestor_out, lock, active) & FillBlock(block1, block1_out, lock, active) & FillBlock(block2, block2_out, lock, active);
+        // output uninitialized. Cast bool to int to avoid -Wbitwise-instead-of-logical
+        // compiler warnings.
+        return int{FillBlock(ancestor, ancestor_out, lock, active)} &
+               int{FillBlock(block1, block1_out, lock, active)} &
+               int{FillBlock(block2, block2_out, lock, active)};
     }
     void findCoins(std::map<COutPoint, Coin>& coins) override { return FindCoins(m_node, coins); }
     double guessVerificationProgress(const uint256& block_hash) override