(partial) Merge bitcoin#21424: Net processing: Tidy up CNodeState ctor

6927933 [net processing] Add ChainSyncTimeoutState default initializers (John Newbery)
55966e0 [net processing] Remove CNodeState ctor body (John Newbery)

Pull request description:

  This addresses the two outstanding review comments from bitcoin#21370.

ACKs for top commit:
  practicalswift:
    cr ACK 6927933: patch looks correct
  hebasto:
    ACK 6927933, I have reviewed the code and it looks OK, I agree it can be merged.

Tree-SHA512: b3ef5c8a096e447887df255406b3a760f01c73e2b942374595416b4b4031fc69b89cd93168c45040489d581f340b2a62d3fbabd207d4307f587c00a7a7daacd1

src/net_processing.cpp

@@ -589,13 +589,13 @@ struct CNodeState {
       */
     struct ChainSyncTimeoutState {
         //! A timeout used for checking whether our peer has sufficiently synced
-        int64_t m_timeout;
+        int64_t m_timeout{0};
         //! A header with the work we require on our peer's chain
-        const CBlockIndex * m_work_header;
+        const CBlockIndex* m_work_header{nullptr};
         //! After timeout is reached, set to true after sending getheaders
-        bool m_sent_getheaders;
+        bool m_sent_getheaders{false};
         //! Whether this peer is protected from disconnection due to a bad/slow chain
-        bool m_protect;
+        bool m_protect{false};
     };
 
     ChainSyncTimeoutState m_chain_sync;