message: Add memory to instance
diff: @@ -9,10 +9,13 @@ namespace fizzy
  struct Instance
  {
  const Module& module;
  + bytes memory;
  };
  namespace
  {
  +constexpr unsigned pagesize = 65536;
  +
  class uint64_stack : public std::vector<uint64_t>
  {
  public:
  @@ -137,7 +140,11 @@ inline uint64_t popcnt64(uint64_t value) noexcept
  Instance instantiate(const Module& module)
  {
  - return {module};
  + // FIXME: set pages from proper section
  + constexpr unsigned pages = 1;
  + // NOTE: fill it with zeroes
  + bytes memory(pages * pagesize, 0);
  + return {module, std::move(memory)};
  }
  execution_result execute(Instance& instance, FuncIdx function, std::vector<uint64_t> args)
  