[net] Remove cs_sendProcessing guard from m_next_addr_send and m_next…

…_local_addr_send

This locking was mistakenly introduced in PR bitcoin#13123.
Related conversation:
bitcoin#13123 (comment)

Making these fields atomic would ensure safety
if multiple RPC accesses them.

src/net.h

@@ -966,8 +966,8 @@ class CNode
     std::vector<CAddress> vAddrToSend;
     std::unique_ptr<CRollingBloomFilter> m_addr_known{nullptr};
     bool fGetAddr{false};
-    std::chrono::microseconds m_next_addr_send GUARDED_BY(cs_sendProcessing){0};
-    std::chrono::microseconds m_next_local_addr_send GUARDED_BY(cs_sendProcessing){0};
+    std::atomic<std::chrono::microseconds> m_next_addr_send{std::chrono::microseconds{0}};
+    std::atomic<std::chrono::microseconds> m_next_local_addr_send{std::chrono::microseconds{0}};
 
     // List of block ids we still have announce.
     // There is no final sorting before sending, as they are always sent immediately

src/net_processing.cpp

@@ -4105,15 +4105,15 @@ bool PeerManager::SendMessages(CNode* pto)
         int64_t nNow = GetTimeMicros();
         auto current_time = GetTime<std::chrono::microseconds>();
 
-        if (pto->RelayAddrsWithConn() && !::ChainstateActive().IsInitialBlockDownload() && pto->m_next_local_addr_send < current_time) {
+        if (pto->RelayAddrsWithConn() && !::ChainstateActive().IsInitialBlockDownload() && pto->m_next_local_addr_send.load() < current_time) {
             AdvertiseLocal(pto);
             pto->m_next_local_addr_send = PoissonNextSend(current_time, AVG_LOCAL_ADDRESS_BROADCAST_INTERVAL);
         }
 
         //
         // Message: addr
         //
-        if (pto->RelayAddrsWithConn() && pto->m_next_addr_send < current_time) {
+        if (pto->RelayAddrsWithConn() && pto->m_next_addr_send.load() < current_time) {
             pto->m_next_addr_send = PoissonNextSend(current_time, AVG_ADDRESS_BROADCAST_INTERVAL);
             std::vector<CAddress> vAddr;
             vAddr.reserve(pto->vAddrToSend.size());