refactor: Use member initializers in CCheckQueue

Summary:
This is a backport of [[bitcoin/bitcoin#18710 | core#18710]] [1/4]
bitcoin/bitcoin@0ef9386

Test Plan: `ninja all check-all`

Reviewers: #bitcoin_abc, Fabien

Reviewed By: #bitcoin_abc, Fabien

Differential Revision: https://reviews.bitcoinabc.org/D10985

src/checkqueue.h

@@ -41,23 +41,23 @@ template <typename T> class CCheckQueue {
     std::vector<T> queue;
 
     //! The number of workers (including the master) that are idle.
-    int nIdle;
+    int nIdle{0};
 
     //! The total number of workers (including the master).
-    int nTotal;
+    int nTotal{0};
 
     //! The temporary evaluation result.
-    bool fAllOk;
+    bool fAllOk{true};
 
     /**
      * Number of verifications that haven't completed yet.
      * This includes elements that are no longer queued, but still in the
      * worker's own batches.
      */
-    unsigned int nTodo;
+    unsigned int nTodo{0};
 
     //! The maximum number of elements to be processed in one batch
-    unsigned int nBatchSize;
+    const unsigned int nBatchSize;
 
     /** Internal function that does bulk of the verification work. */
     bool Loop(bool fMaster = false) {
@@ -135,8 +135,7 @@ template <typename T> class CCheckQueue {
 
     //! Create a new check queue
     explicit CCheckQueue(unsigned int nBatchSizeIn)
-        : nIdle(0), nTotal(0), fAllOk(true), nTodo(0),
-          nBatchSize(nBatchSizeIn) {}
+        : nBatchSize(nBatchSizeIn) {}
 
     //! Worker thread
     void Thread() { Loop(); }