refactor: start BLS thread in LLMQContext ctor, move Start downwards

Alternate fix as proposed in dash#5752, needed because dependencies for
threaded logic will be pulled out of ctor in upcoming commits and that
needs `Start` to be pushed downwards so we can avoid having to pass
`unique_ptr` references.

src/init.cpp

@@ -1906,8 +1906,6 @@ bool AppInitMain(NodeContext& node, interfaces::BlockAndHeaderTipInfo* tip_info)
                                                               *node.mempool, node.mn_activeman.get(), *node.mn_sync, node.peerman, /* unit_tests = */ false, /* wipe = */ fReset || fReindexChainState);
                 // Enable CMNHFManager::{Process, Undo}Block
                 node.mnhf_manager->ConnectManagers(node.chainman.get(), node.llmq_ctx->qman.get());
-                // Have to start it early to let VerifyDB check ChainLock signatures in coinbase
-                node.llmq_ctx->Start();
 
                 node.chain_helper.reset();
                 node.chain_helper = std::make_unique<CChainstateHelper>(*node.cpoolman, *node.dmnman, *node.mnhf_manager, *node.govman, *(node.llmq_ctx->quorum_block_processor), *node.chainman,
@@ -2282,6 +2280,8 @@ bool AppInitMain(NodeContext& node, interfaces::BlockAndHeaderTipInfo* tip_info)
 
     // ********************************************************* Step 10a: schedule Dash-specific tasks
 
+    node.llmq_ctx->Start();
+
     node.scheduler->scheduleEvery(std::bind(&CNetFulfilledRequestManager::DoMaintenance, std::ref(*node.netfulfilledman)), std::chrono::minutes{1});
     node.scheduler->scheduleEvery(std::bind(&CMasternodeSync::DoMaintenance, std::ref(*node.mn_sync), std::cref(*node.peerman), std::cref(*node.govman)), std::chrono::seconds{1});
     node.scheduler->scheduleEvery(std::bind(&CMasternodeUtils::DoMaintenance, std::ref(*node.connman), std::ref(*node.dmnman), std::ref(*node.mn_sync), std::ref(*node.cj_ctx)), std::chrono::minutes{1});

src/llmq/context.cpp

@@ -54,9 +54,13 @@ LLMQContext::LLMQContext(ChainstateManager& chainman, CConnman& connman, CDeterm
     }()},
     ehfSignalsHandler{std::make_unique<llmq::CEHFSignalsHandler>(chainman, mnhfman, *sigman, *shareman, *qman)}
 {
+    // Have to start it early to let VerifyDB check ChainLock signatures in coinbase
+    bls_worker->Start();
 }
 
 LLMQContext::~LLMQContext() {
+    bls_worker->Stop();
+
     // LLMQContext doesn't own these objects, but still need to care of them for consistency:
     llmq::quorumInstantSendManager.reset();
     llmq::chainLocksHandler.reset();
@@ -74,7 +78,6 @@ void LLMQContext::Start() {
     assert(clhandler == llmq::chainLocksHandler.get());
     assert(isman == llmq::quorumInstantSendManager.get());
 
-    bls_worker->Start();
     if (is_masternode) {
         qdkgsman->StartThreads();
     }
@@ -101,5 +104,4 @@ void LLMQContext::Stop() {
     if (is_masternode) {
         qdkgsman->StopThreads();
     }
-    bls_worker->Stop();
 }