Remove unused "topology changed" mechanism

This was never used. It was set but never read and the job list was
never updated.

With the "zombie list" there's no need for it anymore.

Signed-off-by: Sergio Martins <[email protected]>

Author: iamsergio

core/include/gnuradio-4.0/Graph.hpp

@@ -188,7 +188,6 @@ class Graph : public gr::Block<Graph> {
 private:
     std::shared_ptr<gr::Sequence>                     _progress     = std::make_shared<gr::Sequence>();
     std::shared_ptr<gr::thread_pool::BasicThreadPool> _ioThreadPool = std::make_shared<gr::thread_pool::BasicThreadPool>("graph_thread_pool", gr::thread_pool::TaskType::IO_BOUND, 2UZ, std::numeric_limits<uint32_t>::max());
-    std::atomic_bool                                  _topologyChanged{false};
     std::vector<Edge>                                 _edges;
     std::vector<std::unique_ptr<BlockModel>>          _blocks;
 
@@ -341,17 +340,12 @@ class Graph : public gr::Block<Graph> {
         }
         _progress     = std::move(other._progress);
         _ioThreadPool = std::move(other._ioThreadPool);
-        _topologyChanged.store(other._topologyChanged.load(std::memory_order_acquire), std::memory_order_release);
-        _edges  = std::move(other._edges);
-        _blocks = std::move(other._blocks);
+        _edges        = std::move(other._edges);
+        _blocks       = std::move(other._blocks);
 
         return *this;
     }
 
-    void               setTopologyChanged() noexcept { _topologyChanged.store(true, std::memory_order_release); }
-    [[nodiscard]] bool hasTopologyChanged() const noexcept { return _topologyChanged; }
-    void               ackTopologyChange() noexcept { _topologyChanged.store(false, std::memory_order_release); }
-
     [[nodiscard]] std::span<std::unique_ptr<BlockModel>> blocks() noexcept { return {_blocks}; }
     [[nodiscard]] std::span<Edge>                        edges() noexcept { return {_edges}; }