state: Optimize state access thanks to the journal

With the State Journal the backup copy of the state is no longer
performed and the memory addresses of the accounts are not changing
during execution. This allows us to avoid some copies and lookups.

test/state/host.cpp

@@ -315,8 +315,7 @@ evmc::Result Host::execute_message(const evmc_message& msg) noexcept
     if (is_precompile(m_rev, msg.code_address))
         return call_precompile(m_rev, msg);
 
-    // Copy of the code. Revert will invalidate the account.
-    const auto code = dst_acc != nullptr ? dst_acc->code : bytes{};
+    const auto code = dst_acc != nullptr ? bytes_view{dst_acc->code} : bytes_view{};
     return m_vm.execute(*this, m_rev, msg, code.data(), code.size());
 }
 

test/state/state.cpp

@@ -393,7 +393,7 @@ std::variant<TransactionReceipt, std::error_code> transition(State& state, const
     gas_used -= refund;
     assert(gas_used > 0);
 
-    state.get(tx.sender).balance += tx_max_cost - gas_used * effective_gas_price;
+    sender_acc.balance += tx_max_cost - gas_used * effective_gas_price;
     state.touch(block.coinbase).balance += gas_used * priority_gas_price;
 
     // Apply destructs.