Clean up staking tests

[zxcat]

Staking tests contain unused error messages:

cyberway.contracts/tests/cyber.stake_tests.cpp

Line 125 in 753ac8f

const string can_not_be_negative = amsg("quantity can't be negative"); // !! didn't check. TODO: #330

cyberway.contracts/tests/cyber.stake_tests.cpp

Line 128 in 753ac8f

const string nothing_to_cancel = amsg("nothing to cancel"); // !! didn't check. TODO: #330

cyberway.contracts/tests/cyber.stake_tests.cpp

Line 154 in 753ac8f

static bool is_insufficient_ram_mssg(const std::string& arg) { // !! didn't check. TODO: #330

cyberway.contracts/tests/cyber.stake_tests.cpp

Line 157 in 753ac8f

static bool is_costs_too_much_mssg(const std::string& arg) { // !! didn't check. TODO: #330

cyberway.contracts/tests/cyber.stake_tests.cpp

Line 160 in 753ac8f

static bool is_system_err_mssg(const std::string& arg) { // !! didn't check (turned off). TODO: #330

cyberway.contracts/tests/cyber.stake_tests.cpp

Line 172 in 753ac8f

static bool is_block_res_limit_err_mssg(const std::string& arg) { // !! didn't check. TODO: #330

etc… They should be removed if outdated or tests should be updated to use them.

Some checks are exist in the smart-contract, but didn't check in tests:

cyberway.contracts/tests/cyber.stake_tests.cpp

Line 145 in 753ac8f

const string no_agent_exist(account_name agent) { // !! checked only in setinfo tests! TODO: #330