Sapling and Overwinter network upgrades are always active

These NU's are always active for Hush Arrakis Chains so this code only serves
to slow down all operations by constantly being checked. So we disable them
which will speed up syncing, mining and creating transactions.

src/wallet/asyncrpcoperation_shieldcoinbase.cpp

@@ -164,6 +164,7 @@ bool AsyncRPCOperation_shieldcoinbase::main_impl() {
 
     size_t numInputs = inputs_.size();
 
+    /*
     // Check mempooltxinputlimit to avoid creating a transaction which the local mempool rejects
     size_t limit = (size_t)GetArg("-mempooltxinputlimit", 0);
     {
@@ -177,6 +178,7 @@ bool AsyncRPCOperation_shieldcoinbase::main_impl() {
             strprintf("Number of inputs %d is greater than mempooltxinputlimit of %d",
             numInputs, limit));
     }
+    */
 
     CAmount targetAmount = 0;
     for (ShieldCoinbaseUTXO & utxo : inputs_) {