Move ::fCheckBlockIndex into ChainstateManager

This changes the flag for the bitcoin-chainstate executable. Previously
it was false, now it is the chain's default value (still false for the
main chain).

src/init.cpp

@@ -934,8 +934,6 @@ bool AppInitParameterInteraction(const ArgsManager& args, bool use_syscall_sandb
     init::SetLoggingCategories(args);
     init::SetLoggingLevel(args);
 
-    fCheckBlockIndex = args.GetBoolArg("-checkblockindex", chainparams.DefaultConsistencyChecks());
-
     // block pruning; get the amount of disk space (in MiB) to allot for block & undo files
     int64_t nPruneArg = args.GetIntArg("-prune", 0);
     if (nPruneArg < 0) {