message: [Tests] Set public spend activation for regtest to block 400 (from 350)
  This leaves more room to mint, mature and perform v2 spends from PoS
  cache
diff: @@ -462,7 +462,7 @@ public:
  nBlockTimeProtocolV2 = 999999999;
  // Public coin spend enforcement
  - nPublicZCSpends = 350;
  + nPublicZCSpends = 400;
  // Blocks v7
  nBlockV7StartHeight = nPublicZCSpends + 1;
  