Use fixed lower call gas limit

[k1rill-fedoseev]

As part of the AMB a gas limit for the call on the other side can be provided. The provided gas limit is
checked against a minimum gas usage computed based on the number of bytes within a call:

function  getMinimumGasUsage(bytes _data) public pure returns (uint256 gas) {
  // From Ethereum Yellow Paper
  // 68 gas is paid for every non-zero byte of data or code for a transaction
  // Starting from Istanbul hardfork, 16 gas is paid (EIP-2028)
  return _data.length.mul(16);
}

However, as the call is made from within a smart contract, these costs do not apply. They only apply to initial calldata of a transaction. The dominating cost, namely the cost for the CALL itself (increased by EIP-2929) is not considered.