message: fuzz: Avoid -Wreturn-type warnings
diff: #include <attributes.h>
  #include <chainparamsbase.h>
  #include <coins.h>
  +#include <compat.h>
  #include <consensus/consensus.h>
  #include <merkleblock.h>
  #include <net.h>
  @@ -545,11 +546,13 @@ public:
  SOCKET Get() const override
  {
  assert(false && "Not implemented yet.");
  + return INVALID_SOCKET;
  }
  SOCKET Release() override
  {
  assert(false && "Not implemented yet.");
  + return INVALID_SOCKET;
  }
  void Reset() override
  